The spec already carries the pre-separation mixdown as a stem
({id: full, file: stems/full.ogg}), so the key added a second, redundant
location for audio to a format that already had one. Adopting it into the
spec would make that permanent; the resolution in #933 is to remove it.
No behaviour change — the gate is agnostic about which way a violation
resolves, and only insists that one of the two happens deliberately and in
the open before the code merges. This just stops the exception entry, the
changelog, and the docs from presupposing adoption.
Signed-off-by: topkoa <topkoa@gmail.com>