$ git clone -n https://src.fedoraproject.org/rpms/swayimg.git /var/lib/mock/f42-build-side-1-3537686-46560/root/chroot_tmpdir/scmroot/swayimg
Cloning into '/var/lib/mock/f42-build-side-1-3537686-46560/root/chroot_tmpdir/scmroot/swayimg'...
$ git fetch origin ecfda47dcdbe1e33164f7b5f8d8d5265b52aafd9:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/swayimg
 * [new ref]         ecfda47dcdbe1e33164f7b5f8d8d5265b52aafd9 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ecfda47 Update to 4.2 (#2371135)