(srclib contributor here) srclib is a bit higher level. Its goal is to be able to look at any source tree and automatically detect languages, packages, build config, etc. We're actually looking at using some of Kythe's lower level analyzers to invoke after srclib auto-detects and auto-configures the build.

srclib also has an API that makes it easy to build editor plugins that are language independent. Check out the editor plugins dropdown at https://srclib.org/overview/ for a list.

Other folks can check out what srclib is able to infer on various projects at https://sourcegraph.com/ (which is powered by srclib).

or to pfff: https://github.com/facebook/pfff