The "test-comment-format" command:

Usage: fossil test-comment-format ?OPTIONS? PREFIX TEXT ?ORIGTEXT?

Test comment formatting and printing.  Use for testing only.

Options:
  --file           The comment text is really just a file name to
                   read it from.
  --decode         Decode the text using the same method used when
                   handling the value of a C-card from a manifest.
  --legacy         Use the legacy comment printing algorithm.
  --trimcrlf       Enable trimming of leading/trailing CR/LF.
  --trimspace      Enable trimming of leading/trailing spaces.
  --wordbreak      Attempt to break lines on word boundaries.
  --origbreak      Attempt to break when the original comment text
                   is detected.
  --indent         Number of spaces to indent (default (-1) is to
                   auto-detect).  Zero means no indent.
  -W|--width <num> Width of lines (default (-1) is to auto-detect).
                   Zero means no limit.