$ git clone -n https://src.fedoraproject.org/rpms/libpng15.git /var/lib/mock/f41-build-729147-13151/root/chroot_tmpdir/scmroot/libpng15
Cloning into '/var/lib/mock/f41-build-729147-13151/root/chroot_tmpdir/scmroot/libpng15'...
$ git fetch origin 25314f98ba2adecd03bd7313622b7cda49cfa395:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libpng15
 * [new ref]         25314f98ba2adecd03bd7313622b7cda49cfa395 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 25314f9 Eliminate use of obsolete %patchN syntax (#2283636)