A casino operator runs the site, handles accounts and payments, and chooses...

https://wiki-neon.win/index.php/Why_Do_Some_Slot_Layouts_Break_on_Different_Screen_Sizes%3F

A casino operator runs the site, handles accounts and payments, and chooses which games to list. A slot provider makes the game. Provider names help identify who built a title. Visuals and sound may differ, but they do not change the game rules.