$ git clone -n https://src.fedoraproject.org/rpms/irstlm.git /var/lib/mock/f41-build-785984-13590/root/chroot_tmpdir/scmroot/irstlm
Cloning into '/var/lib/mock/f41-build-785984-13590/root/chroot_tmpdir/scmroot/irstlm'...
$ git fetch origin 3bca86591c0bb9cb40299fa923fddec3ca446c36:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/irstlm
 * [new ref]         3bca86591c0bb9cb40299fa923fddec3ca446c36 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3bca865 Eliminate use of obsolete %patchN syntax (#2283636)