@rijnard (the blog post author) is awesome, and all of the code changes he talks about in the blog post are public. You can see all of his recent changes to search code in <a href="https://sourcegraph.com/search?q=context:global+repo:%5Egithub%5C.com/sourcegraph/sourcegraph%24+type:diff+author:rijnard+f:search&patternType=literal" rel="nofollow">https://sourcegraph.com/search?q=context:global+repo:%5Egith...</a> in case you want to follow along by just reading the code (that query shows all of his diffs that touch paths containing `search`).