Modified by the Overworld Indicators patch. This value is the SRAM size in the original game, and it's changed to $02 to expand to 4KB of SRAM in case Ragey's Overworld Expansion is enabled. (Only does this if SRAM is 2KB, e.g. default value)
Hijacked by the Retry System (+ Multiple Checkpoints) v2.06b patch by worldpeace and LX5.
Part of the sram expansion patch included in retry. It modifies the SRAM size byte in the ROM header, if !midway_sram = 1. Otherwise it writes the original value ($01).