The scraper read emulatorLauncher master on every run, so an extractor
change was diffed together with upstream's commits since the pin. It now
rereads the commit platforms/retrobat.yml pins. --revision master moves
it, and check_freshness and refresh_stale pass that through the
registry's rescrape_args.
The extractors also read master (f681f435): Kronos and YabaSanshiro
fall back to sega_101.bin then mpr-17933.bin when the chosen BIOS is
absent, Ymir writes a forced BIOS only under its override flag, and a
folder created below bios (Ymir's cdb) is a passes_path record. At the
pin the 187 records are unchanged.