I guess Google will still index dormant repos.

Github's search is inferior compared to google's site search for github (i.e keyword site:github.com).

I don't know why but Github search almost useless if the thing you are searching for is not a exact match. For example I tried just one random search. Search keyword: HashMapBoxing https://github.com/google/guava/search?q=HashMapBoxing

No results for me, however here is one that contains word IdentityHashMapBoxing https://github.com/google/guava/blob/master/guava-tests/test...

So I almost stopped using it. Either I use google search or I just clone the repo and use my IDE.

Edit: Ok, this search also fails with Google search, but still :)