In the ashelp project we used sqlite3 databases as container for HTML help files, sort of like an opensource CHM format and archive and the ashelp application itself was the viewer. The Tkhtml widget used for it (v3) made trouble on some platforms IIRC.

There was the idea of possible storing these archives in the teapot, for installation alongside with their packages, and modifying the viewer to automatically look for them in a local repository. This was never followed up on nor completed.