$ git clone -n https://src.fedoraproject.org/rpms/javacc-maven-plugin.git /var/lib/mock/f40-build-2530189-61829/root/chroot_tmpdir/scmroot/javacc-maven-plugin
Cloning into '/var/lib/mock/f40-build-2530189-61829/root/chroot_tmpdir/scmroot/javacc-maven-plugin'...
$ git fetch origin 9dc8ec2e88bc079ff166c58c968f54355391bcd1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/javacc-maven-plugin
 * [new ref]         9dc8ec2e88bc079ff166c58c968f54355391bcd1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9dc8ec2 Version 3.1.0