Because these builds contain copyrighted games, they are hosted on the official Batocera.linux website . You can typically find them on community-driven sites:

Before you click that mysterious "Batocera 33 Download REPACK" magnet link, consider these serious risks:

which typically refers to a pre-configured version of the Batocera operating system that comes with a massive library of games and media. Batocera 33

When you boot into Batocera, you are greeted immediately by a controller-friendly interface (EmulationStation). Behind the scenes, it utilizes a suite of the world’s best emulators (RetroArch, Dolphin, PCSX2, PPSSPP, etc.) to run games from systems ranging from the Atari 2600 to the PlayStation 3, Nintendo Switch, and Sega Dreamcast.