Does anyone know what those are?

Is legacy hardware still necessary, if this leaked WinXP source code would somehow enable or accelerate the development of non-commercial virtual machine-solutions, similar to DOSBox or the console emulators?
Of course, you couldn't then "officially" use any of those WinXP VMs, especially for commercial purposes...

No, Wine works perfectly fine for that. Judging from the number of "Windows 10 broke muh old game!" posts I see, it's easier to play old Windows games on Mac/Linux rather than Windows these days. So you just need someone to get Wine to work on Windows.

As useful as the Nintendo source code leak was to the Dolphin emulator, which is to say, zero usefulness at all. In order to stay legal and do clean-room reverse-engineering, you can't so much as glance at source code.

tbh I don't care much.
I don't get why people like XP much, I only used to to run 1 old game... it is good for really old games.

You can look for more malicious code, code which likely exists in 7 8 & 10.

Also, the code may be more usable than we think. Consider, if the current copyright law (70+life or 110 years for a corporation) gets reduced and the actual purpose of copyright (giving sole ownership for a short limited to make a profit) gets restored? Think if corporations can't sit on a library of games and sell them infinitely forever and instead have to *GASP* make games to stay profitable.

At this point it's apparent games ownership past 20 years doesn't really do anything, as companies will just do a 'remake' or 'rerelease' over and over again and the corporations get lazy and greedy. Within 4 years Discs and books are out of print and it's what's in stock but hasn't been sold.

So if a push for copyright to drop the Mickymouse copyright extention to something reasonable, the source code could actually lead to an alternate OS that many would enjoy using (at least in emulators, VM's, or in certain limited hardware)

I don't think it's particularly likely, and the proof would be of the "reasonable doubt" variety, not 100% iron-clad. Also, just found this:
https://www.reddit.com/r/linux_gaming/comments/j08dh8/windows_xp_source_code_got_leaked_how_helpful_is/

That was interesting, thanks!

I question how long we'll have a current OS for a typical desktop style open system, that's more what I was thinking. Eric is probably correct right below you though, that Linux or a similar OS would take over that role and emulate Windows.

engadget isn't 4chan. No one asked you to link to something stupid like that. It's just customary when you post news, you post a source for it.
I guess I shouldn't be surprised that the likes of you frequents 4chan.

I wish MS would release the source code for the most recent DOS versions, it could really benefit DOSbox.

Cool, this is useless.

I imagine that enough of hardware, microcode, and software have moved on from the 5.X series of the NT Kernel as to render this utterly useless.

Not to mention the legal barricades.

I do not even go to 4chan I only saw it through a resetera.com topic which had 4chan described in there.
Speaking of Source Code.

Imagine if MicroSoft just officially released the Source Code for Windows XP, DirectX 9, Windows Vista and all of DirectX 10. Then eventually for Windows 7.

sadly this is something Microsoft will never do, because Microsoft is not a good company.
https://www.youtube.com/watch?v=TIfNIWn2Ad4
This video shows a anti competitive practice they used to get rid of another company.

Microsoft is also highly anti opensource, they might look like they give linux some support but really it is a tactic to get rid of it someday. Microsoft buying bethesda will make the games they make not use Vuklan making it a lot harder to run games on linux now...

Considering Microsoft built DOS and the first Windows off stolen code, it's no wonder they would not release anything. Windows actually came about from a contract they had with apple to help develop a GUI for the APPLE ][. They breached that contract and copied many of the visual element designs they were given as a base for the system.