As someone still having an Nintendo Developer Portal account, holding SCEE content back when the London Soho office used to have a developer site (aka Team Soho), and PS2Linux owner, there is plenty of material that can be discussed publicly without breaking NDAs.
Console specific information also is not all that interesting anymore these days since game consoles have switched to off-the-shelf GPU designs with only minor modifications.
Even the current generation of consoles still have some interesting stuff going on. The 'core' of the console is fairly off the shelf, but they do still have modifications specific to the console that you won't find elsewhere. As far as GPU stuff goes, they tend to provide somewhat lower-level access to the hardware that you would normally not get with consumer stuff.
