searchcode - A source code search engine
Sourcegraph - Sourcegraph is a free, self-hosted code search and intelligence server that helps developers find, review, understand, and debug code. Use it with any Git code host for teams from 1 to 10,000+.
CRX Extractor - Get any Chrome Extension source code. Learn and hack!
OpenGrok - OpenGrok is a fast and usable source code search and cross reference engine.
Relevance - No code interface to customize search rankings
GrepCode - GrepCode.com is a code search engine built by developers for developers to search and browse open...