The "/leaves" page:
Show leaf check-ins in a timeline.  By default only open leaves
are listed.
A "leaf" is a check-in with no children in the same branch.  A
"closed leaf" is a leaf that has a "closed" tag.  An "open leaf"
is a leaf without a "closed" tag.
Query parameters:
    all           Show all leaves
    closed        Show only closed leaves
    ng            No graph
    nohidden      Hide check-ins with "hidden" tag
    onlyhidden    Show only check-ins with "hidden" tag
    brbg          Background color by branch name
    ubg           Background color by user name