https://tiddlywiki.com/#Improving%20TiddlyWiki%20Documentation
GitHub and the Pull Request (PR) model is used to suggest changes to documentation on the main site at tiddlywiki.com. Follow the link to get basic instructions on how to use GitHub / make PRs.
The tiddlywiki-com branch is what is used as the source for the website. Changes made here go live immediately on the website. The actual source tiddlers can be viewed at this link https://github.com/Jermolene/TiddlyWiki5/tree/tiddlywiki-com/editions/tw5.com/tiddlers.
Changes meant for the next release (i.e. to document new features of the upcoming release) should go in the master branch.
The Documentation Style Guide is the start of instructions of the style in which to write.
In addition, @pmario has made a number of videos explaining the process, which are also embedded below:
