$ git clone -n https://src.fedoraproject.org/rpms/libtracefs.git /var/lib/mock/f45-build-17151-496/root/chroot_tmpdir/scmroot/libtracefs
Cloning into '/var/lib/mock/f45-build-17151-496/root/chroot_tmpdir/scmroot/libtracefs'...
$ git fetch origin 6ef27d62dbd3d814124b3d5951839e4b7f57d4c6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libtracefs
 * [new ref]         6ef27d62dbd3d814124b3d5951839e4b7f57d4c6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6ef27d6 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild