INES Mapper 101
This mapper is used for instance by Urusei Yatsura - Lum no Wedding Bell, the Famicom version of Jaleco's Momoko 120%.
Supported in r3420 BizHawk, r2696 FCEUX (probably has been supported for eons), and reportedly MESS.
Registers: --------------------------- $6000-7FFF: [CCCC CCCC] C = Selects 8k CHR @ $0000
This is the same as mapper 87 but with the bits in order, or the same as CNROM without bus conflicts.
This mapper seems to be a naive misdumping of the JF-10 board that contains Urusei Yatsura. JF-10 is identical to JF-09, which is the only mapper 87 game with 32KiB CHR. Both JF-10 and JF-09 only differ from all their predecessors (JF-05, -06, -07, and -08) by the addition of a single trace. In short, either mapper 87 should be capped to 16KiB CHR, or mapper 101 never had a hardware instantiation. In any case, mapper 101 has a better defined oversize extension.