        Show summary information about the current or specified topic
        branch.

        Numbers in parenthesis after a branch name such as "(11/3 commits)"
        indicate how many commits on the branch (11) and how many of those
        are non-merge commits (3).

        With `--verbose` (or `-v`) include a list of dependents (i.e. other
        branches that depend on this one).  Another `--verbose` annotates
        them with "[needs merge]" if the current tip of branch for which info
        is being shown has not yet been merged into the base of the dependent.
        Two `--verbose` options also cause annihilated dependencies to be
        shown in the "Depends:" list.

        Alternatively, if `--heads` is used then which of the independent
        TopGit branch heads (as output by `tg summary --topgit-heads`)
        logically contains the specified commit (which may be any committish --
        defaults to `HEAD` if not given).  Zero or more results will be
        output.  Note that "logically" means with regard to the TopGit
        dependency relationships as established by the `.topdeps` file(s).
        It's the answer that would be given when all the TopGit branches are
        up-to-date (even though they need not be to use this option) and the
        `git branch --contains` command is run and the output then filtered
        to only those branches that appear in `tg summary --topgit-heads`.
        This computation may require several seconds on complex repositories.

        If `--leaves` is used then the unique list of leaves of the current
        or specified topic branch is shown as one fully-qualified ref per line.
        Duplicates are suppressed and a tag name will be used when appropriate.
        A "leaf" is any dependency that is either not a TopGit branch or is
        the base of a non-annihilated TopGit branch with no non-annihilated
        dependencies.

        The `--deps` option shows non-annihilated TopGit dependencies of the
        specified branch (default is `HEAD`).  (It can also be spelled out
        as `--dependencies` for the pedantically inclined.)

        The `--dependents` option shows non-annihilated TopGit dependents
        (i.e. branches that depend on the specified branch).  The default
        branch to operate on is again `HEAD`.

        A linearized patch series can only be automatically created for a
        TopGit topic branch (including its recursive dependencies) when exactly
        one line is output by `tg info --leaves <topic-branch>`.

        With `--series` the list of TopGit branches in the order they would
        be linearized into a patch series is shown along with the description
        of each branch.  If the branch name passed to `tg info` is not the
        last branch in the series a marker column will be provided to quickly
        locate it in the list.  This same option can be used with "tg checkout".

        Some patches shown in the list may not actually end up introducing any
        changes if exported and will therefore end up being omitted.  The `0`
        indicator in `tg summary` output can help to identify some of these.

        The patches shown in the series in the order they are shown form the
        basis for the `tg next` and `tg prev` operations with the first
        patch shown being considered the first and so on up to the last.

