$ git clone -n https://src.fedoraproject.org/rpms/rubygem-sinatra.git /var/lib/mock/f45-build-35321-694/root/chroot_tmpdir/scmroot/rubygem-sinatra
Cloning into '/var/lib/mock/f45-build-35321-694/root/chroot_tmpdir/scmroot/rubygem-sinatra'...
$ git fetch origin b2e334d0aef54b1ac04943de1e406116e10b66f5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-sinatra
 * [new ref]         b2e334d0aef54b1ac04943de1e406116e10b66f5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b2e334d Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild