Those are noble goals, but I think your project ignores a few important things:

- The internet has become the primary distribution channel of software itself, not just documentation. How would a user be in the position to access software via the internet, but not its documentation? They can't purchase software offline in a brick and mortar store anymore, and physical media is pretty much dead. They would need to keep the software updated on a regular basis, and downloading a few kilobytes of documentation pales in comparison to downloading hundreds of megabytes of software. So the internet really is a requirement for most software, even for those that can function entirely offline, and most developers make this assumption.

- What fraction of those 2.9B people who are not yet online would a) use traditional computers instead of tablets and smartphones, b) be interested in OSS, c) actually have a need for and the patience to read documentation? I reckon that this is a very small percentage, constituting orders of magnitude less people than the billions you claim it is.
Instead, most people would be better served by using intuitive devices and software that doesn't require documentation to begin with. Smartphones and smartphone apps have made computing more accessible to more users than personal computers, desktop operating systems and mountains of documentation ever did. The next generation of computing devices will be even more intuitive, and written documentation wouldn't even make sense to new users.

- The quality of the documentation is more important than how it's accessible. It doesn't matter if I can read documentation offline, if it's incomplete, incorrect or confusing. There are no manifestos that will make developers write good documentation. This is either something they care about and put effort in, or they don't.

- The advent of LLMs is making traditional documentation obsolete. Why would any user prefer going through a bunch of documentation of varying quality to find the information they need, when an LLM could give them the right answer tailored to their query, much more quickly and in a consistent language? LLMs make knowledge more discoverable than traditional documentation.
Even projects like DevDocs will not remain useful for too long. Proprietary LLMs like ChatGPT can already do a decent job at this, and other products can be trained on specific documentation. Accessibility is still a hurdle, but this too will improve with local, offline and open source LLMs, lower hardware requirements, etc. Soon there won't be a need to write documentation at all, as AI will be able to answer any functional question about software directly, which it can already do to an extent. Once it becomes better at writing software itself better than humans, documentation as we think of it today will be even less of a necessity.

So I really don't think your initiative has as much importance, or will have as much of an impact, that you think it does and will. At best, offline documentation removes a minor inconvenience for a small subset of computer users _today_. And these users already have solutions like DevDocs and, increasingly, LLMs at their disposal.