OpenGrok
OpenGrok is a fast and usable source code search and cross reference engine. It helps you search, cross-reference and navigate your source tree. In other words it lets you grok (profoundly understand) source code and is developed in the open, hence the name OpenGrok.
These are the available (incomplete) groks with DragonFly BSD:
http://grok.dragonflybsd.org
Self-hosted by the DragonFly project
Also grok the DPorts third-party packages!http://BXR.SU/DragonFly/
DragonFly BSD on Super User's BSD Cross Reference
very fast
You can also set up your own OpenGrok.