The "/tree" page:

Show the files using a tree-view.  If the ci= query parameter is present
then show only the files for the check-in identified.  If ci= is omitted,
then show the union of files over all check-ins.

The type=tree query parameter is required or else the /dir format is
used.

Query parameters:

   type=tree        Required to prevent use of /dir format
   name=PATH        Directory to display.  Optional
   ci=LABEL         Show only files in this check-in.  Optional.
   re=REGEXP        Show only files matching REGEXP.  Optional.
   expand           Begin with the tree fully expanded.
   nofiles          Show directories (folders) only.  Omit files.
   mtime            Order directory elements by decreasing mtime