If this were about PR it wouldn't be a post to a technical mailing list about a single document being dropped and mention of work going on to provide more (but unlikely all) docs in the future.
Just because two things happen on the same day (or within a week of each other, etc) doesn't mean they're closely connected.
Having worked closely with silicon vendors in the past, the situation that there are no internal docs or that the docs are horribly outdated or incorrect compared to the HDL or source code, is pretty common. When the only consumer of docs is an internal team, it's not uncommon for those docs to be nowhere near what an external team would expect or need (or a company would be willing to release without serious cleanup and checking).
>If this were about PR it wouldn't be a post to a technical mailing list //
You're probably right.
That said your view of PR seems naive. It looks far better to release on social networks that someone found that CompanyN was "already" working on something than it does that there's an official press release. The channel used here - mailing list to social networks - doesn't tell us much IMO.
>it's not uncommon for those docs to be nowhere near what an external team would expect or need //
You think they'd be worse than the nothing that is currently provided by many hardware manufacturers.
Just because two things happen on the same day (or within a week of each other, etc) doesn't mean they're closely connected.
Having worked closely with silicon vendors in the past, the situation that there are no internal docs or that the docs are horribly outdated or incorrect compared to the HDL or source code, is pretty common. When the only consumer of docs is an internal team, it's not uncommon for those docs to be nowhere near what an external team would expect or need (or a company would be willing to release without serious cleanup and checking).