With EGIT_CLONE_TYPE="shallow" the following happens when trying to emerge ffmpeg-9999 (clone or fetch) > git clone https://git.ffmpeg.org/ffmpeg.git +HEAD:refs/git-r3/HEAD --depth=1 > Cloning into '+HEAD:refs/git-r3/HEAD'... > fatal: The remote end hung up unexpectedly > fatal: protocol error: bad pack header I suppose the problem is the `--depth=1` being appended at the end rather than specified directly after `clone`.
(`fetch`, that is. In the above example I just reproduced the error manually.)
That's a problem with the server. You can workaround it by setting EGIT_MIN_CLONE_TYPE.