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 Only a web interface or CLI
Fossil's bug tracker only works with the web interface or the command-line interface. There's no native GUI client supporting it.
There are some independent GUI clients out there, but none of them support Fossil's full range of abilities.