The builder and the coverage report each grouped their own candidates
before asking which regional alternatives to withdraw. The builder
grouped the platform files and the core extras; the report grouped the
platform files alone, and keyed them on an unsanitized destination.
So a region run withdrew 73 files from a recalbox pack while the report
withdrew 14, and described the other 59 as covered by a pack that would
not carry them.
platform_region_groups builds the grouping once and both sides read it.
The extras it returns are keyed by emulator, name and path: Dolphin
declares three IPL.bin that differ by path alone, and a name-keyed map
withdraws the wrong one. Manifests are byte-identical before and after.
Abdessamad Derraz