Commit 8403487d introduced in the chroot stage a naming scheme for local
archive keys which distinguishes between ASCII-armored keys and binary
ones, and then adds the appropriate extension (either `.asc` or `.gpg`,
respectively) when copying them to `/etc/apt/trusted.gpg.d`.
However, this change was not applied to the binary stage: ASCII-armored
and binary keys are still both copied with the `.asc` extension, which
introduces a discrepancy between the two stages. This, in turn,
may prevent using the same `.list` file for both stages, as entries
such as
deb [signed-by=/etc/apt/trusted.gpg.d/my-repository.key.asc] ...
will fail in the chroot stage if `config/archives/my-repository.key`
is in binary format (as it will be copied with the `.gpg` extension),
while entries such as
deb [signed-by=/etc/apt/trusted.gpg.d/my-repository.key.gpg] ...
will fail in the binary stage (as the key will this time be copied
with the `.asc` extension).