$ git clone -n https://src.fedoraproject.org/rpms/cosmic-files.git /var/lib/mock/f41-build-857450-168097/root/chroot_tmpdir/scmroot/cosmic-files
Cloning into '/var/lib/mock/f41-build-857450-168097/root/chroot_tmpdir/scmroot/cosmic-files'...
$ git fetch origin 1e38d6b4b962bb7656bf32a512a6a4aecd10bdae:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/cosmic-files
 * [new ref]         1e38d6b4b962bb7656bf32a512a6a4aecd10bdae -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 1e38d6b Import package (1.0.0~alpha.2)