The "/whatis" page:

Typical usage:

   /artifact/HASH
   /whatis/HASH
   /file/NAME

Additional query parameters:

  ln              - show line numbers
  ln=N            - highlight line number N
  ln=M-N          - highlight lines M through N inclusive
  ln=M-N+Y-Z      - highlight lines M through N and Y through Z (inclusive)
  verbose         - show more detail in the description
  download        - redirect to the download (artifact page only)
  name=NAME       - filename or hash as a query parameter
  filename=NAME   - alternative spelling for "name="
  fn=NAME         - alternative spelling for "name="
  ci=VERSION      - The specific check-in to use with "name=" to
                    identify the file.

The /artifact page show the complete content of a file
identified by HASH.  The /whatis page shows only a description
of how the artifact is used.  The /file page shows the most recent
version of the file or directory called NAME, or a list of the
top-level directory if NAME is omitted.

For /artifact and /whatis, the name= query parameter can refer to
either the name of a file, or an artifact hash.  If the ci= query
parameter is also present, then name= must refer to a file name.
If ci= is omitted, then the hash interpretation is preferred but
if name= cannot be understood as a hash, a default "tip" value is
used for ci=.

For /file, name= can only be interpreted as a filename.  As before,
a default value of "tip" is used for ci= if ci= is omitted.