Map of all XBA RNG rooms
In the following map, all those rooms are highlighted (in green and orange) in which either acid or lava is set to exist, which coincides with those rooms in which during gameplay frames the RNG value's high byte is swapped exactly once with it's low byte (for example 0x1234 turns into 0x3412). In green rooms, this is always the case, but in orange rooms only as long as a certain room state is active. In Mother Brain's room, the XBA (eXchange byte B with byte A) is applied to the RNG only in the first 2 room states but not in the final room state when the acid moves away and MB2 fight begins. In the Climb room, the XBA effect is only existing in the Tourian escape room state. The XBA effect allows the path that RNG takes to change, whereas outside of XBA-affected rooms, the (direction and) path that RNG takes (from any one value to the next) is fixed and runs into a loop of RNG values (and can there only change the speed at which it moves through this loop). The blue rooms are the remaining rooms in which no XBA is applied to the RNG.