For a new plugin, I am working on, I need a way to get the UserId or Username of the creator of a given asset. I have searched the Developer Hub for functions of all the relevant services, and I still cannot figure out a way to do this. The closest thing I could find was MarketplaceService:PlayerOwnsAsset(player, assetid). It would determine whether the player created an asset most of the time, but would still return true for an asset purchased from the library by the player.
If there is an alternative way to detect who created an asset via custom script functions, I am open to that as well.