LTS ISO assembly results in on forked repositories.
```
(11:03) vyos_bld f5b93e5fddc6:/vyos/vyos-build-circinus [liveboot] # isobuild -liveboot
Building custom VyOS version: 1.5-liveboot-202606281103
E: Could not retrieve vyos-1x from branch circinus: GitCommandError(['git', 'checkout', 'circinus'], 1, b"error: pathspec 'circinus' did not match any file(s) known to git", b'')
```