I can only assume this will be related to a content involving the Trust Companions in later contents.

Maybe Trust Companion quests?

Or something else since right now we have the bare bone version of Trust once we complete 5.0 MSQ and the Trust system we have during 5.0 MSQ is the Trial version.

I always expect that trust will become something more than just "help players get through MSQ Story Dungeons for 5.0 and beyond for the first time" that we currently have now.