It won't update (sibling) branches, that are checked out.

      --update-refs, --no-update-refs
           Automatically force-update any branches that point to commits that
           are being rebased. Any branches that are checked out in a worktree
           are not updated in this way.

           If the configuration variable rebase.updateRefs is set, then this
           option can be used to override and disable this setting.