The code itself isn't something I'm actively maintaining at the moment, it's in dire need of rebuilding, and will need it even more so after HF20.

If you're not looking to adopt HF20 for the fork, what exists on Github might be a good starting place for the code, but it's very likely it won't receive any further updates until after HF20. If you are planning on adopting HF20 in your fork, I'd recommend waiting for new explorer code or perhaps as the HF enters testnets, trying your own hand at it :)