The article compares UK and US online slot rules, including testing, payout...

https://mill-wiki.win/index.php/How_can_I_tell_if_a_slot_site_is_UK_licensed%3F

The article compares UK and US online slot rules, including testing, payout information and state-by-state access. A 96.5% RTP is an example, not a promise of individual returns; legal options for online casino play vary widely across the US.