The "timeline" command:

Usage: fossil timeline ?WHEN? ?BASELINE|DATETIME? ?-n N? ?-t TYPE? ?-showfiles?

Print a summary of activity going backwards in date and time
specified or from the current date and time if no arguments
are given.  Show as many as N (default 20) check-ins.  The
WHEN argument can be any unique abbreviation of one of these
keywords:

    before
    after
    descendants | children
    ancestors | parents

The BASELINE can be any unique prefix of 4 characters or more.
The DATETIME should be in the ISO8601 format.  For
examples: "2007-08-18 07:21:21".  You can also say "current"
for the current version or "now" for the current time.

The optional TYPE argument may any types supported by the /timeline
page. For example:

    w  = wiki commits only
    ci = file commits only
    t  = tickets only

The optional showfiles argument, if specified, prints the list of
files changed in a checkin after the checkin comment.