git worktree help inconsistent

Using git 2.6.1

In git command line usage, Please mark <branch> optional, the man page is correct.

$ git worktree add
usage: git worktree add [<options>] <path> <branch>
   or: git worktree prune [<options>]

    -f, --force           checkout <branch> even if already checked
out in other worktree
    -b <branch>           create a new branch
    -B <branch>           create or reset a branch
    --detach              detach HEAD at named commit

But in man page, git worktree add [-f] [--detach] [-b <new-branch>] <path> [<branch>] git worktree prune [-n] [-v] [--expire <expire>]