I'm on the Kythe team, and I don't know off the top of my head what Zoekt is. Looking it up, I see it's some sort of trigram search, which means if it's used at all (I have no idea), it's codesearch proper, not Kythe.
The Kythe index is the semantic index of the codebase, Codesearch does all of the text/regex/etc searching.
Are you sure? There is find definition and references in https://cs.opensource.google/bazel/bazel and Im quite sure it's thanks to the Kythe indexing job Bazel team is running in CI.
The refs & jump to def in bazel/bazel are using Kythe, yes. But that is Kythe's semantic index from running (also it's Kythe team running it, not bazel team). It's not the Codesearch trigram/text search (which again, I have no idea if it uses zoekt).
I'm on the Kythe team, and I don't know off the top of my head what Zoekt is. Looking it up, I see it's some sort of trigram search, which means if it's used at all (I have no idea), it's codesearch proper, not Kythe.
The Kythe index is the semantic index of the codebase, Codesearch does all of the text/regex/etc searching.