$ git clone -n https://src.fedoraproject.org/rpms/pcm.git /var/lib/mock/f41-build-side-1-2971446-35827/root/chroot_tmpdir/scmroot/pcm
Cloning into '/var/lib/mock/f41-build-side-1-2971446-35827/root/chroot_tmpdir/scmroot/pcm'...
$ git fetch origin 2df89d69aee8b7f601592d8121e7b29f94dd3b49:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/pcm
 * [new ref]         2df89d69aee8b7f601592d8121e7b29f94dd3b49 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 2df89d6 fix the build