The is a specific collection of ROMs used primarily with the FBA 2012 (FinalBurn Alpha 2012) libretro core. It is the recommended ROM version for many popular handheld systems, such as the Miyoo Mini running Onion OS .
Collectors love this specific set because it represents the "sweet spot" before the shift to FBNeo, yet after the major bug fixes. A standard full set for v0.2.97.29 typically contains between (depending on clones and bootlegs).
In emulation, the software (emulator) and the data (ROMs) must match. Arcade game files are frequently "dumped" (extracted from chips) in different ways over time. As emulators update, they often stop supporting older file formats in favor of better, more accurate ones.