$ git clone -n https://src.fedoraproject.org/rpms/libreport.git /var/lib/mock/f40-build-2242173-53669/root/chroot_tmpdir/scmroot/libreport
Cloning into '/var/lib/mock/f40-build-2242173-53669/root/chroot_tmpdir/scmroot/libreport'...
$ git fetch origin 3d476b7c77a27fee1f9cc335ac011346964b744d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libreport
 * [new ref]         3d476b7c77a27fee1f9cc335ac011346964b744d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 3d476b7 Fix build with libxml2 2.12