The XR_EXT_active_action_set_priority extension.

The properties of an XrActionSet become immutable after it has been attached to a session. This currently includes the priority of the action set preventing the application from changing the priority number for the duration of the session.

Given that most runtimes do not actually require this number to be immutable this extension adds the ability to provide a different priority number for every XrActiveActionSet provided to SyncActions.

When updating the action state with SyncActions, the application can provide a pointer to an XrActiveActionSetPrioritiesEXT structure in the next chain of XrActionsSyncInfo. This structure contains an array of XrActiveActionSetPriorityEXT structures mapping active action sets to their priority numbers.