Fossil includes a bug-tracker, along with source-code management and a wiki, and technotes - all in a distributed model. It's the system that supports sqlite development.
Ranked in these QuestionsQuestion Ranking
Pro Very easy to configure as self-hosted.
Single, stand-alone executable, including web server.
Pro Very complete
Fossil includes source code management, bug tracking, a wiki, and technotes.
It even includes its own web server, though it can fairly easily be incorporated into other webservers.
Fossil can run on Linux, Mac, BSD derivatives and on Windows.
A Fossil repository is contained in a single file.
Pro Needs very few server resources
Since Fossil is a distributed VCS on top of being a bug tracker, it needs very few server resources.
Con No official GUI available
Fossil sports a command-line interface (CLI). Most of the repository can be viewed using the built-in web interface, but checkin (commit), update and merge manipulations can only be done from the CLI.
There are some independent GUI clients out there, but none of them support Fossil's full range of abilities.