This is the list for currently supported Atari XL/XE games. You shouldn’t need any configuration to run these games, you only need the game media (atr/xex) and use the name in the code column.
This is an example of valid games
retrox/atari/bcquest.xex retrox/atari/bluemax2001.atr retrox/atari/bmxsimulator.xex
Note the use of the names bcquest and bluemax2001, according to the table those codes will help RetroX detect which games are, and it will use the configuration that was already tested for RetroX.