$ git clone -n https://src.fedoraproject.org/rpms/perl-Date-Calc-XS.git /var/lib/mock/f42-build-876212-179677/root/chroot_tmpdir/scmroot/perl-Date-Calc-XS
Cloning into '/var/lib/mock/f42-build-876212-179677/root/chroot_tmpdir/scmroot/perl-Date-Calc-XS'...
$ git fetch origin 02f6c3aa78a041f556c582f70e6dba611b03fb6a:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/perl-Date-Calc-XS
 * [new ref]         02f6c3aa78a041f556c582f70e6dba611b03fb6a -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 02f6c3a Add 0001-Fix-bool-detection.patch (F42FTBS, RHBZ#2341026).