Our documentation website https://docs.tvheadend.org has changed behind the scenes and is now based on the content of https://github.com/tvheadend/documentation. The old v4.0 documentation site is still visible here.
GitBook are hosting everything for us and their browser-based markdown editor makes it simple for anyone to join the project documenation team and submit changes: whether that's a simple typo correction or more substantial additions. The underlying workflow for GitBook is (as the name suggests) git-based, so user changes made in GitBook are summarised into a pull-request, which a member of the project staff can review and merge into the underlying repo. It is also possible for anyone to edit content directly in GitHub and add files the repo in the same way as god, but this requires greater git and markdown knowledge.
Tvheadend documentation hasn't been "current" since v4.0 in 2016 so it will take time to merge documentation files and wiki content and fix things up. Once we feel new documenation is in better shape than old documentation we will make changes to the build-system in our main code repo to include new documentation "sources" with our binaries so we continue to ship local documentation aligned to the features of the Tvheadend version being built.
Online documentation is currently English language only. In the long-term it would be nice to have localised content but it is more important for the project to have one source of current documentation in English than three outdated ones partially translated to other languages.
NB: Please do not be concerned about how good your English is when contributing documentation changes. It is much easier for a native speaker to merge your content then make some corrections than to write everything from scratch themselves. And if there is no obvious place to put the content (right now the structure is sparse and incomplete) create content on a separate page. It can be merged and moved around later as the documentation structure evolves.
Click here to join the documentation team on GitBook and help out