[briandoll]

I checked the Reddit post, the FAQ and the IndexTank website, and there was no mention of the underlying technology implementation. It says that it uses a subset of Lucene, but no further details.

Is this basically hosted Solr with some tweaks for speed and features?

[jhandl]

No, the old search was Solr based, this one uses only the lucene index file structure. Not even the scorer is lucene-based.