In the help message for the `unmark` command, this is shown.  It seems to suggest that only one Index can be entered, due to the missing `...` after `INDEX`. According to the UG, there should be `...` present.  <!--session: 1731658452176-ff093243-da7a-4eb3-97c5-c63fd9778a5f--><!--Version: Desktop v3.5.4-->