FF8/FileFormat RAT MRT
Field Rate and battle Formations (Encounter)
MRT file contains 4 * two bytes. Each two bytes is a battle formation ID.
RAT file contains 4 bytes. Each byte is the battle frequency, they are always equal, but only the first is used by the game.
If rate equal zero, there is no encounter, if rate equal 255, there are often battles. Known values: 4, 6, 8, 10, 12 and 16.