A popular tool where you simply drag and drop the data.rsdk file onto the extractor to generate "data" and "unknown" folders containing sprites and media.
Navigate to your install location through the Manage menu next to the "Uninstall" button. sonic mania plus data.rsdk
To access your legitimate copy of the data.rsdk file, you must first own the game on a PC platform. A popular tool where you simply drag and drop the data