In this case, a sort of official news source would be the game provider's website.
RTP is not a thing anybody would willingly and officially lower. ?? It can vary across the casinos, based on the contry you come from, just an example.
Casinos should show slots's RTP so players can decide whether it's worth the try, a decent RTP starts at 96%.
Did you know that some game providers allow casinos to pick the RTP they prefer to provide to players?
Generaly, most players reffer to the lower RTP - Retur to player - when they feel, they have lost more that deposited.
Interested to learn how it works for slots?
Just an example:
"If a game RTP is 96%, it means that if you start with $1,000,000,000 and then play 1,000,000,000 rounds at $1 each, then you should end up with approximately $960,000,000 dollars."
Check out this guide.
Automatic translation: