$ git clone -n https://src.fedoraproject.org/rpms/rubygem-aws-sigv4.git /var/lib/mock/f45-build-34797-691/root/chroot_tmpdir/scmroot/rubygem-aws-sigv4
Cloning into '/var/lib/mock/f45-build-34797-691/root/chroot_tmpdir/scmroot/rubygem-aws-sigv4'...
$ git fetch origin 5e4c2e284c618741b8b04bedf55b18945f4e8de1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-aws-sigv4
 * [new ref]         5e4c2e284c618741b8b04bedf55b18945f4e8de1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5e4c2e2 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild