I think the closest that this has come is in the form of GitLab, which pretty famously did a ton of the corporate work in the format of a very open Handbook (https://handbook.gitlab.com/)
In the early years, it was extremely, extremely open and comprehensive. I've definitely looked through it when I wasn't sure how to handle something at work.
And that site is available as a git repository - on Gitlab of course:
https://gitlab.com/gitlab-com/content-sites/handbook
That's pretty cool. Wonder if it is deployed and updated religiously still. If they wanted to deploy an 'Agent' worker that source is goldmine for context.
I don't know about "religiously" but as of right now it was last updated 16 minutes ago:
https://gitlab.com/gitlab-com/content-sites/handbook