Djblets 6.0 is a large release, featuring caching improvements, new

dynamic page state injection support, general rate limiting, cache

locks, layered siteconfig lookups, new templatetag support, and a whole

lot more.
This change introduces the release notes for this release, covering

usage information and examples where appropriate.
Given how much is going on in this release, sub-sections have been used

to introduce the major new changes within a module's section, and

examples have been added to help clarify how most of these work. This

will be the pattern going forward, and should also help with any AI bots

that want to learn from our releases.

Built the docs. Checked for bad links, build errors, and any obvious

errors in the text.