diff --git a/Makefile.rkt b/Makefile.rkt
index 1f1babb..b5058ad 100644
--- a/Makefile.rkt
+++ b/Makefile.rkt
@@ -21,6 +21,9 @@
         (deps clean)
         (zip-package))
 
+(target zip
+        (deps package))
+
 (define doc-target "docs/git.html")
 (define doc-src "scribblings/git.scrbl")
 
diff --git a/info.rkt b/info.rkt
index a55034b..82c8ad7 100644
--- a/info.rkt
+++ b/info.rkt
@@ -2,7 +2,7 @@
 
 (define collection "git-cli")
 (define pkg-desc "Command-line-like Git operations for Racket, interface to the git cli command")
-(define version "0.3.11")
+(define version "0.3.14")
 (define pkg-authors '("Hans Dijkema"))
 (define license 'MIT)
 
diff --git a/main.rkt b/main.rkt
index 98a59e6..e78fac5 100644
--- a/main.rkt
+++ b/main.rkt
@@ -18,6 +18,12 @@
          git-push
          git-log
          git-grep
+         git-branch
+         git-clone
+         git-rev-list
+         git-diff
+         git-help
+         git-version
          git-new-version
          )
 
@@ -31,10 +37,12 @@
 ;; Command invocation using 'git'
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-;; goal: Invoke a supported Git command through the command table.
-;; pre: command is a registered Git command symbol.
-;; post: The selected command has processed all supplied arguments.
-;; result: The command-specific result.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Invoke a supported Git command through the command table.
+; pre    : command is a registered Git command symbol.
+; post   : The selected command has processed all supplied arguments.
+; result : The command-specific result.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (define (git command . args)
   ((hash-ref git-commands command
@@ -46,11 +54,23 @@
 ;; Supporting functions
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Read one line of input after displaying a prompt.
+; pre    : p can be displayed.
+; post   : The prompt has been flushed before input is read.
+; result : The entered line or an EOF object.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (git-prompt p)
   (display p)
   (flush-output)
   (read-line))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Add --porcelain to a Git argument list when it is absent.
+; pre    : args is a list and an optional transformation accepts a list.
+; post   : Existing porcelain options have not been duplicated.
+; result : The transformed Git argument list.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (add-porcelain args info . f)
   (let ((m (has-git-arg? args #px"^[-][-]porcelain([=](.*))?"))
         (g (if (null? f) (λ (x) x) (car f)))
@@ -59,6 +79,12 @@
         (g args)
         (g (cons '--porcelain args)))))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Convert one porcelain status character to a semantic symbol.
+; pre    : status is one Git porcelain v1 status character.
+; post   : Unknown status characters have raised an exception.
+; result : The corresponding semantic status symbol.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (status->symbol status)
   (cond
     ((string=? status " ") 'unchanged)
@@ -73,6 +99,12 @@
     ((string=? status "!") 'ignored)
     (else (error 'git-status "Unexpected status: ~a" status))))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Recognize Git output that reports there is nothing to commit.
+; pre    : out is a list of Git output lines.
+; post   : out has only been inspected.
+; result : #t when a known nothing-to-commit message occurs, otherwise #f.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (nothing-to-commit? out)
   (ormap (λ (line)
            (let ((line* (string-downcase line)))
@@ -84,6 +116,12 @@
 ;; Command definition macro
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Define and register a public Git command procedure.
+; pre    : pre-code and process-result follow the command proxy interfaces.
+; post   : cmd-sym is registered in the generic git command table.
+; result : Definitions for the public and internal command procedures.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define-syntax def-cmd
   (syntax-rules ()
     ((_ cmd cmd* cmd-sym)
@@ -104,10 +142,12 @@
 ;; Typical git commands
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
-;; goal: Return the complete Git index and worktree status for every reported file.
-;; pre: The current directory is inside a Git working tree.
-;; post: Git status has been invoked with --porcelain.
-;; result: A list containing (index-status worktree-status file) for every file.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return the complete Git index and worktree status for every reported file.
+; pre    : The current directory is inside a Git working tree.
+; post   : Git status has been invoked with --porcelain.
+; result : A list containing (index-status worktree-status file) for every file.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-status cmd-git-status 'status
   add-porcelain
   (λ (cmd exit-code result output out info)
@@ -126,16 +166,20 @@
   )
 
 
-;; goal: Add file contents to the Git index.
-;; pre: The supplied arguments are valid for git add.
-;; post: Git add has completed successfully or an exception has been raised.
-;; result: #t after a successful Git command.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Add file contents to the Git index.
+; pre    : The supplied arguments are valid for git add.
+; post   : Git add has completed successfully or an exception has been raised.
+; result : #t after a successful Git command.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-add cmd-git-add 'add)
 
-;; goal: Create a Git commit.
-;; pre: A commit message is supplied or can be requested from the user.
-;; post: The commit was created, nothing needed committing, or an exception was raised.
-;; result: #t after a commit or when the repository has nothing to commit.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Create a Git commit.
+; pre    : A commit message is supplied or can be requested from the user.
+; post   : The commit was created, nothing needed committing, or an exception was raised.
+; result : #t after a commit or when the repository has nothing to commit.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-commit cmd-git-commit 'commit
   (λ (args info)
     (with-handlers ([exn:fail? (λ (e)
@@ -154,48 +198,121 @@
        (std-process-git-result cmd exit-code result output out info))))
   )
 
-;; goal: Push local changes to a remote repository.
-;; pre: The supplied arguments are valid for git push.
-;; post: Git push has completed successfully or an exception has been raised.
-;; result: #t after a successful push.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Push local changes to a remote repository.
+; pre    : The supplied arguments are valid for git push.
+; post   : Git push has completed successfully or an exception has been raised.
+; result : #t after a successful push.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-push cmd-git-push 'push add-porcelain)
 
-;; goal: Fetch and integrate changes from a remote repository.
-;; pre: The supplied arguments are valid for git pull.
-;; post: Git pull has completed successfully or an exception has been raised.
-;; result: #t after a successful pull.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Fetch and integrate changes from a remote repository.
+; pre    : The supplied arguments are valid for git pull.
+; post   : Git pull has completed successfully or an exception has been raised.
+; result : #t after a successful pull.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-pull cmd-git-pull 'pull)
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : List, create or delete branches.
+; pre    : The supplied arguments are valid for git branch.
+; post   : Git branch has completed successfully or an exception was raised.
+; result : #t after a successful branch command.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-branch cmd-git-branch 'branch)
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Clone a repository into a new directory.
+; pre    : The supplied arguments are valid for git clone.
+; post   : The clone exists or an exception was raised.
+; result : #t after a successful clone.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-clone cmd-git-clone 'clone)
 
-;; goal: Display the Git commit log.
-;; pre: The supplied arguments are valid for git log.
-;; post: Git log has completed successfully or an exception has been raised.
-;; result: #t after successfully displaying the log.
-(def-cmd git-log cmd-git-log 'log)
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Display the Git commit log or return it as a Racket list.
+; pre    : The supplied arguments are valid for git log; --list and -l are git-cli options.
+; post   : Git log has completed successfully or an exception has been raised.
+; result : A list of (commit subject) items with --list/-l, otherwise #t.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+(def-cmd git-log cmd-git-log 'log
+  (λ (args info)
+    (map (λ (e)
+           (let ((o (format "~a" e)))
+             (cond
+               ((or
+                 (string=? o "--list")
+                 (string=? o "-l"))
+                (begin
+                  (hash-set! info 'scheme-format #t)
+                  "--oneline"))
+               (else e))))
+         args))
+  (λ (cmd exit-code result output out info)
+    (if (hash-ref info 'scheme-format #f)
+        (if (and (= exit-code 0) result)
+            (let ((re #px"([0-9a-f]+)\\s+(.*)"))
+              (map (λ (line)
+                     (let ((m (regexp-match re line)))
+                       (if m
+                           (list (cadr m) (caddr m))
+                           (list #f line))))
+                   out))
+            #f)
+        (std-process-git-result cmd exit-code result output out info)))
+  )
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : List commit objects reachable from supplied revisions.
+; pre    : The supplied arguments are valid for git rev-list.
+; post   : Git rev-list has completed successfully or an exception was raised.
+; result : #t after successfully displaying the result.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-rev-list cmd-git-rev-list 'rev-list)
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Render a Git diff in the default browser.
+; pre    : The supplied arguments are valid for git diff or
+;          are special cases like --output=-, --output=string.
+; post   : A successful diff has been rendered as HTML or
+;          to stdout/string.
+; result : #t or a string when a diff was rendered, otherwise #f.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-diff cmd-git-diff 'diff
-  (λ (args info) args)
+  (λ (args info)
+    (hash-set! info 'file-output (has-git-arg? args #px"^[-][-]output[=]"))
+    (hash-set! info 'stdout (has-git-arg? args #px"^[-][-]output[=][-]"))
+    (hash-set! info 'string (has-git-arg? args #px"^[-][-]output[=]string"))
+    (if (or (hash-ref info 'stdout #f) (hash-ref info 'string #f))
+        (filter (λ (e) (not (has-git-arg? (list e) #px"^[-][-]output[=]([-]|string)"))) args)
+        args))
   (λ (cmd exit-code result output out info)
     (if (and (zero? exit-code)
              result)
-        (let ((diff (string-join 
-                     (filter (λ (line)
+        (if (eq? (hash-ref info 'file-output #f) #f)
+            (let ((diff (string-join 
+                         (filter (λ (line)
                                (not (string-prefix? (string-downcase line) "warning:")))
-                             out)
-                     "\n")))
-          (diff->html diff)
-          #t)
-          #f)))
+                                 out)
+                         "\n")))
+              (diff->html diff)
+              #t)
+            (if (hash-ref info 'string #f)
+                (string-join out "\n")
+                (std-process-git-result cmd exit-code result output out info)))
+        (std-process-git-result cmd exit-code result output out info))))
 
-;; goal: Search tracked files for a pattern.
-;; pre: The supplied arguments are valid for git grep.
-;; post: Git grep has completed; exit code one is treated as no matches.
-;; result: A list containing file, line number, match count and matched text.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Search tracked files for a pattern.
+; pre    : The supplied arguments are valid for git grep.
+; post   : Git grep has completed; exit code one is treated as no matches.
+; result : A list containing file, line number, match count and matched text.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-grep cmd-git-grep 'grep
   (λ (args info)
     (let ((matches #f)
@@ -244,6 +361,13 @@
             #f))))
   )
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Display help for Git or a Git command.
+; pre    : The supplied arguments are valid for git help.
+; post   : Git help has completed successfully or an exception was raised.
+; result : #t after successfully displaying help.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (def-cmd git-help cmd-git-help 'help)
 
 
@@ -251,21 +375,41 @@
 ;; Racket module versioning
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Return the package version from info.rkt.
+; pre    : No arguments are required.
+; post   : info.rkt has only been inspected.
+; result : A list containing major, minor and patch.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (git-version . args)
   (cmd-git-version args))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Implement the registered version command.
+; pre    : args is the command argument list.
+; post   : info.rkt has only been inspected.
+; result : A list containing major, minor and patch.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (cmd-git-version args)
   (info-version "."))
 
 (hash-set! git-commands 'version cmd-git-version)
 
-;; goal: Increment the package version in info.rkt.
-;; pre: kind is 'maj, 'major, 'min, 'minor or 'patch.
-;; post: The version definition in info.rkt has been updated.
-;; result: The new version as a list containing major, minor and patch.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Increment the package version in info.rkt.
+; pre    : kind is 'maj, 'major, 'min, 'minor or 'patch.
+; post   : The version definition in info.rkt has been updated.
+; result : The new version as a list containing major, minor and patch.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (git-new-version . args)
   (cmd-git-new-version args))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Implement the registered new-version command.
+; pre    : args contains a supported version kind.
+; post   : The version definition in info.rkt has been updated.
+; result : The new version as a list containing major, minor and patch.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (cmd-git-new-version args)
   (when(null? args)
       (error "git-new-version expects 'maj, 'major, 'min, 'minor or 'patch"))
diff --git a/private/config.rkt b/private/config.rkt
index d7999d3..f4c33b8 100644
--- a/private/config.rkt
+++ b/private/config.rkt
@@ -43,11 +43,24 @@
 ;; Provided functions
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Store one git-cli configuration value.
+; pre    : section and key identify a simple-ini setting.
+; post   : value has been persisted.
+; result : The result returned by simple-ini.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (cfg-set! section key value)
   (critical
    (check-ini)
    (send ini set! section key value)))
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Read one git-cli configuration value.
+; pre    : section and key identify a simple-ini setting.
+; post   : Configuration has not been changed.
+; result : The stored value or default-value.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (cfg-get section key default-value)
   (critical
    (check-ini)
diff --git a/private/diff.rkt b/private/diff.rkt
index d680a32..75fed8e 100644
--- a/private/diff.rkt
+++ b/private/diff.rkt
@@ -11,6 +11,12 @@
 (define (make-js . args)
   (string-join args "\n"))
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Render a Git diff in a temporary HTML file.
+; pre    : diff is a unified Git diff string.
+; post   : The generated HTML file has been opened in the default browser.
+; result : void.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (diff->html diff)
   (let ((highlight-css "https://cdnjs.cloudflare.com/ajax/libs/highlight.js/11.8.0/styles/github.min.css")
         (diff2html-min-css "https://cdn.jsdelivr.net/npm/diff2html/bundles/css/diff2html.min.css")
diff --git a/private/git-commands.rkt b/private/git-commands.rkt
index 6f8425d..5dbf9a2 100644
--- a/private/git-commands.rkt
+++ b/private/git-commands.rkt
@@ -12,6 +12,12 @@
          )
 
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Determine whether a Git option occurs in an argument list.
+; pre    : args is a list and opt is a symbol, string or regular expression.
+; post   : args has only been inspected.
+; result : The match result, or #f when the option is absent.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (has-git-arg? args opt)
   (let ((cmp (cond ((symbol? opt) (λ (x) (eq? x opt)))
                    ((string? opt) (λ (x) (string=? (format "~a" x) opt)))
@@ -28,6 +34,13 @@
           (f args)
           (error 'has-git-arg? "args must be a list of arguments")))))
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Check that mandatory Git options and their arguments are present.
+; pre    : flags contains (option argument-count error-message) items.
+; post   : Missing options have raised an exception.
+; result : args when every mandatory option is present.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (check-git-args cmd args flags)
   (for-each
    (λ (opt)
@@ -51,10 +64,12 @@
   args)
 
 
-;; goal: Process the standard result of a Git command.
-;; pre: exit-code and out belong to the completed Git command.
-;; post: Successful output has been displayed or a Git exception has been raised.
-;; result: #t when exit-code is zero.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Process the standard result of a Git command.
+; pre    : exit-code and out belong to the completed Git command.
+; post   : Successful output has been displayed or a Git exception has been raised.
+; result : #t when exit-code is zero.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (std-process-git-result cmd exit-code result output out info)
   (if (= exit-code 0)
       (begin
@@ -65,10 +80,12 @@
   )
 
 
-;; goal: Define the internal proxy for a Git command.
-;; pre: pre-code and process-result accept the command proxy arguments.
-;; post: The proxy invokes Git without standard input and processes its result.
-;; result: A procedure named f accepting a list of Git arguments.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Define the internal proxy for a Git command.
+; pre    : pre-code and process-result accept the command proxy arguments.
+; post   : The proxy invokes Git without standard input and processes its result.
+; result : A procedure named f accepting a list of Git arguments.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define-syntax def-git-cmd-proxy
   (syntax-rules ()
     ((_ f cmd pre-code process-result)
diff --git a/private/git-provider.rkt b/private/git-provider.rkt
index fde9f9c..dc054bf 100644
--- a/private/git-provider.rkt
+++ b/private/git-provider.rkt
@@ -47,6 +47,12 @@
 ;; Provided functions
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Find the configured Git executable.
+; pre    : Git is on PATH or a valid executable can be selected interactively.
+; post   : The executable path has been cached.
+; result : The path to git or git.exe.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define/contract (git-exe)
   (-> (or/c path? #f))
   (if (eq? cached-git-exe #f)
@@ -64,6 +70,13 @@
         the-git-exe)
       cached-git-exe))
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Configure the Git executable.
+; pre    : exe-path names an executable path.
+; post   : The path has been stored and cached.
+; result : void.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define/contract (set-git-exe! exe-path)
   (-> path? void?)
   (void
@@ -72,6 +85,13 @@
      (set! cached-git-exe exe-path))))
 
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Run Git without allowing interactive terminal prompts.
+; pre    : args contains the Git command and its arguments.
+; post   : Standard output and error have been read completely.
+; result : The exit code and ordered (source line) output items.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (run-git args)
   (putenv "GIT_TERMINAL_PROMPT" "0")
   (let-values (((process stdout stdin stderr)
@@ -123,6 +143,13 @@
 (define (is-error? e)
   (not (is-output? e)))
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Separate normal Git output from error output.
+; pre    : output contains (source line) items returned by run-git.
+; post   : output has only been inspected.
+; result : Whether no error occurred and either normal or error lines.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (git-out cmd output)
   (let* ((out (map (λ (e) (cadr e)) (filter (λ (e) (is-output? e)) output)))
          (err (map (λ (e) (cadr e)) (filter (λ (e) (is-error? e)) output)))
@@ -130,6 +157,13 @@
          )
     (values r (if (eq? r #t) out err))))
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Log and raise a Git exception.
+; pre    : cmd, msg* and outp describe a failed Git command.
+; post   : The message has been logged and an exception has been raised.
+; result : No normal return value.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define-syntax git-error
   (syntax-rules ()
     ((_ cmd msg* outp)
@@ -153,6 +187,13 @@
 
 (define re-a #px"~+")
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Log Git output and optionally display it.
+; pre    : out is a string or a list of displayable lines.
+; post   : Non-empty output has been logged.
+; result : void.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (git-displ out)
   (let ((str (if (string? out) out (string-join out "\n"))))
     (unless (string=? (string-trim str) "")
diff --git a/private/info.rkt b/private/info.rkt
index 1f0ef33..c686ed3 100644
--- a/private/info.rkt
+++ b/private/info.rkt
@@ -9,6 +9,12 @@
          git-next-version
          )
 
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Read a package version from info.rkt.
+; pre    : dir contains a readable info.rkt.
+; post   : info.rkt has only been inspected.
+; result : A list containing major, minor and patch.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (info-version dir)
   (let* ((l (get-info/full dir))
          (re #px"([0-9]+)[.]([0-9]+)([.]([0-9]+))?")
@@ -23,6 +29,13 @@
                                       (cadddr (cdr m)))))
     ))
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Store a package version in info.rkt.
+; pre    : dir contains info.rkt and version parts are numbers.
+; post   : The version definition has been replaced.
+; result : #t after writing the file.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (set-info-version! dir maj min patch)
   
   (define (write-version fh)
@@ -54,6 +67,13 @@
             #t)))))
   )
 
+
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
+; goal   : Increment a package version.
+; pre    : kind is maj, major, min, minor or patch.
+; post   : The version definition in info.rkt has been updated.
+; result : #t after writing the new version.
+;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 (define (git-next-version kind . dir*)
   (let ((dir (if (null? dir*)
                  "."
diff --git a/scribblings/git.scrbl b/scribblings/git.scrbl
index 7a79fd9..dcdd8e9 100644
--- a/scribblings/git.scrbl
+++ b/scribblings/git.scrbl
@@ -1,8 +1,8 @@
 #lang scribble/manual
 
 @(require (for-label racket/base
+                     racket/contract
                      "../main.rkt"))
-@;git-cli))
 
 @title[#:tag "top"]{git-cli}
 @author{Hans Dijkema}
@@ -10,18 +10,27 @@
 @defmodule[git-cli]
 
 The @racketmodname[git-cli] module provides a command-line-like Git interface
-implemented by invoking the @tt{git} executable. Commands never read from
-standard input.
+implemented by invoking the @tt{git} executable. Commands do not allow Git to
+read credentials or other answers from the terminal.
+
+@section{Command interface}
 
 @defform[(git command argument ...)]{
-Runs a supported Git @racket[command]. The arguments are passed to the Git
-command. Supported commands include @racket['status], @racket['add],
+Runs a registered Git @racket[command]. The arguments are passed to the command.
+Registered command symbols are @racket['status], @racket['add],
 @racket['commit], @racket['push], @racket['pull], @racket['branch],
 @racket['clone], @racket['log], @racket['rev-list], @racket['diff],
 @racket['grep], @racket['help], @racket['version], and
 @racket['new-version].
+
+Most registered commands invoke the Git command with the same name. Some
+commands process the result into a Racket value, such as @racket['status],
+@racket['grep], @racket['log] with @tt{--list}, @racket['version], and
+@racket['new-version].
 }
 
+@section{Provided commands}
+
 @defproc[(git-status [argument any/c] ...) list?]{
 Runs @tt{git status --porcelain} with the supplied arguments.
 
@@ -37,11 +46,11 @@ Both statuses are one of @racket['unchanged], @racket['modified],
 are @racket['untracked].
 
 @racketblock[
-((modified unchanged "staged.rkt")
- (unchanged modified "working-tree.rkt")
- (modified modified "both.rkt")
- (renamed unchanged "old.rkt -> new.rkt")
- (untracked untracked "new.rkt"))
+'((modified unchanged "staged.rkt")
+  (unchanged modified "working-tree.rkt")
+  (modified modified "both.rkt")
+  (renamed unchanged "old.rkt -> new.rkt")
+  (untracked untracked "new.rkt"))
 ]}
 
 @defproc[(git-add [argument any/c] ...) boolean?]{
@@ -62,11 +71,27 @@ status zero; otherwise an exception is raised.
 
 @defproc[(git-pull [argument any/c] ...) boolean?]{
 Fetches and integrates changes. Normal progress written by Git to standard
-error is treated as output when Git exits successfully.
+error is accepted when Git exits successfully.
 }
 
-@defproc[(git-log [argument any/c] ...) boolean?]{
+@defproc[(git-log [argument any/c] ...) (or/c boolean? list?)]{
 Displays Git log output and returns @racket[#t] when Git exits successfully.
+
+The git-cli-specific option @tt{--list}, or its short form @tt{-l}, changes the
+result to a Racket list. Internally this option is replaced by Git's
+@tt{--oneline} option. Each returned item contains the abbreviated commit id and
+the commit subject.
+
+@racketblock[
+(git-log '--list '-5)
+
+'(("003f371" "Diverse commando's toegevoegd. Ik weet nog niet of ik ze allemaal ga houden")
+  ("2cb7e93" "Small changes. git main function is now a real function, not syntax"))
+]
+
+Other Git log options are still passed to Git. Consequently, options that add
+extra output lines can also influence how useful @tt{--list} is as a structured
+result.
 }
 
 @defproc[(git-grep [argument any/c] ...) list?]{
@@ -75,6 +100,8 @@ optional match count, and matched text. Exit status one means that no matches
 were found and returns an empty list.
 }
 
+@section{Package version}
+
 @defproc[(git-new-version [kind symbol?]) list?]{
 Updates the version in @filepath{info.rkt}. The kind is @racket['major],
 @racket['minor], or @racket['patch], with @racket['maj] and @racket['min] as