$ git clone -n https://src.fedoraproject.org/rpms/rubygem-sys-uname.git /var/lib/mock/f45-build-35383-695/root/chroot_tmpdir/scmroot/rubygem-sys-uname
Cloning into '/var/lib/mock/f45-build-35383-695/root/chroot_tmpdir/scmroot/rubygem-sys-uname'...
$ git fetch origin cc7650b02e6f4ad047d7cd8d615fac258ef914b7:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-sys-uname
 * [new ref]         cc7650b02e6f4ad047d7cd8d615fac258ef914b7 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at cc7650b Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild