Called by:

• Mobilizon.Federation.ActivityPub.Types.Events.join (L151)
• Mobilizon.Federation.ActivityPub.Types.Events.do_approve (L225)
• Mobilizon.Federation.ActivityPub.Types.Events.do_approve (L239)
• Mobilizon.GraphQL.Resolvers.Participant.confirm_participation_from_token (L285)