$ git clone -n https://src.fedoraproject.org/rpms/libe-book.git /var/lib/mock/f42-build-862627-170967/root/chroot_tmpdir/scmroot/libe-book
Cloning into '/var/lib/mock/f42-build-862627-170967/root/chroot_tmpdir/scmroot/libe-book'...
$ git fetch origin 8e2cb0e5604dcd43d7be2459ed88e13afd4c64b1:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/libe-book
 * [new ref]         8e2cb0e5604dcd43d7be2459ed88e13afd4c64b1 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 8e2cb0e Rebuild for ICU 76