$ git clone -n https://src.fedoraproject.org/rpms/rubygem-mysql2.git /var/lib/mock/f42-build-865341-173025/root/chroot_tmpdir/scmroot/rubygem-mysql2
Cloning into '/var/lib/mock/f42-build-865341-173025/root/chroot_tmpdir/scmroot/rubygem-mysql2'...
$ git fetch origin c200d75f704393d4eab2fced0f2fb45333a0e354:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-mysql2
 * [new ref]         c200d75f704393d4eab2fced0f2fb45333a0e354 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at c200d75 Rebuilt for https://fedoraproject.org/wiki/Changes/Ruby_3.4