Comment (by Roland Haas):

Non existent functions in an AFTER or BEFORE (and also IN) clause in schedule.ccl are allowed in Cactus.They can for example be defined by thorns that are not included in the thornlist (and may be private). Eg BSSN_RegisterVars may be of that type. However your list also contains some that would seem to be in IllinoisGRMHD itself so their exclusion looks like a bug to me.

Assigning to the ILGRMHD author (and maintainer) @Zach Etienne

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Ticket URL: https://bitbucket.org/einsteintoolkit/tickets/issues/2576/after-statements-in-scheduler-in