Metabug to capture work to port individual pages from the MDN archived Firefox/Gecko docs to firefox-source-docs. File a bug when you grab a page.
The MDN team removed Gecko and Mozilla internals from MDN last year. There are about 8000 pages in the archive, with varying age and accuracy/staleness. Some of the pages are useful for historical reference, it's unclear what we want to do with those. However, some other pages usefully document how Gecko and Firefox work today, and those are clearly worth pulling into the maintained firefox-source-docs repository.
Right now, there's work underway to generate a comprehensive list of docs worth porting.
In the meantime, feel free to file a bug here if you see a page you would like to pull over.
The archived repo is here: https://github.com/mdn/archived-content/tree/main/files/en-us
I'll include a link to the megadoc when it's been narrowed down further (hopefully down to 500-1000 pages of possible interest), and when we identify the (say) 50 most valuable pages, we'll plan to file bugs for those under this metabug.