man page for "git-worktree" is a bit confusing WRT "prune"

  once more, into the man pages ... "git worktree" seems like a fairly
simple command, but there is some confusion about the function of

  $ git worktree prune

the normal meaning of "prune" (certainly with git commands) is to actually delete some content, and the initial impression of this command is that it will delete an actual worktree. however, further reading reveals:

" ... or you can run git worktree prune in the main or any linked working tree to clean up any stale administrative files."

  ah, so one learns that the subcommand "prune" does *not* do any
actual pruning as people would *normally* understand it, it simply
deletes the administrative information about an already-deleted
worktree, do i read that correctly?

  that's emphasized further down in the actual definition of "prune":

    prune
        Prune working tree information in $GIT_DIR/worktrees.

but perhaps that explanation could be extended to say it only works on already-deleted trees, since that's certainly not clear from that single sentence.

  finally, the prune "--expire" option is truly confusing:

    --expire <time>
        With prune, only expire unused working trees older than <time>.

suddenly, we encounter the verb "expire", which means ... what? how does "expiring" a worktree differ from "pruning" a worktree? and what makes a worktree "unused"? the normal meaning of "unused" is that you haven't, you know, *used* it lately. in this context, though, does it mean deleted? and if it means deleted, what does it mean for it to be older than some time if it's already gone?

  thoughts?

rday