The "blame" command:

Usage: fossil (annotate|blame|praise) ?OPTIONS? FILENAME

Output the text of a file with markings to show when each line of
the file was last modified.  The "annotate" command shows line numbers
and omits the username.  The "blame" and "praise" commands show the user
who made each check-in and omits the line number.

Options:
  --filevers                  Show file version numbers rather than
                              check-in versions
  -l|--log                    List all versions analyzed
  -n|--limit N                Only look backwards in time by N versions
  -w|--ignore-all-space       Ignore white space when comparing lines
  -Z|--ignore-trailing-space  Ignore whitespace at line end

See also: info, finfo, timeline