$ git clone -n https://src.fedoraproject.org/rpms/mingw-boost.git /var/lib/mock/f45-build-18394-515/root/chroot_tmpdir/scmroot/mingw-boost
Cloning into '/var/lib/mock/f45-build-18394-515/root/chroot_tmpdir/scmroot/mingw-boost'...
$ git fetch origin 9dad75ac382d23da4216c6e75c43546c146c7a80:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/mingw-boost
 * [new ref]         9dad75ac382d23da4216c6e75c43546c146c7a80 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 9dad75a Rebuild (icu)