Re: decompilation. It is not magically legal just because you want it to be.
If you took footage of the thing in action, played the game, noted how high you jumped and how many frames it took, made an equation for that (or maybe a lookup table) and implemented that into your own game before rinsing and repeating for all the other jumps, movement, swimming, flying, trees, wall hits, enemy behaviours, object behaviours, sound behaviours, damage, extra caps, the camera... then that would potentially be in the realm of something called clean room reverse engineering and thus debatably legal in some jurisdictions (though this would be most of the big ones). If that amount of work sounds like a nightmare that would decades you are correct -- you tend to only see it for simple communication protocols, file formats and the like. There are some blurry edges as well -- looking at memory might be OK (various courts have ruled it is user data) and using a cheat device to enable the nice debug mode might be as well but disassembly (which is a precursor to decompilation in most cases, certainly in this one) is not and likely never will be. There are further exceptions for things and related matters like stolen code investigations (more on that in a later part of this reply), interoperability (one of the main things that allows emulators to be legal, or at least one of the major hurdles anybody seeking for emulators to be made legally dubious would have to overcome), access for disabilities in some cases, backups in some cases, restoring dead code in some cases and a few other things.
Even after all that level design, music and graphics still reach the level of copyright and you also have the problems with trademarks and maybe some forms of trade dress (Mario's red and blue scheme probably has something) if you wanted to call the resulting project super mario 64 [something].
I don't know why Nintendo have not been as harsh/all burn it all and salt the fields as they usually are here but were I to be playing lawyer I would not be banking on getting my client's decompilation project suit from Nintendo being thrown out as legit code, a frivolous lawsuit or the like (saving that Nintendo filed improperly or something, which is unlikely as they most likely have full time big boy lawyers on staff and a big firm on retainer for outside purposes) -- damage control would be the main task there.
All that said. Beer on me should any devs of the decompilation and I ever meet at a conference or something and everybody else keep sharing those tapes.
Re: hybrid. It is a marketing term for a handheld with a TV out port and a USB hub. We have seen it several times before in various forms official and unofficial and it is not exactly a radical concept at any point since we started having things able to plug into a screen.
There may be something to this whole hybrid lark (would probably involve notable extra somewhat local computing oomph, a bit of "cloud processing" not going to cut it really, and not just a mild clock change that can be run on a normal battery quite happily) but here is a marketing term. Don't read anything into it and instead look at games (or the lack thereof).
How would you prove that, though?
Usual way to detect someone used stolen code or stolen documentation is there will be errors within the documentation. Someone blindly copying that will implement the same error, or maybe something is done in a slightly long winded way, that neither the original hardware nor any game running upon it will use. You spot this error or long winded way in the final product and you have your case.
Can you specify? People started a rumor about them stealing public dumps of roms from online but that was proven false
No that was true, and you can still grab dumps and see for yourself if you really wanted. They had ROMs pulled from their emulators that had ines headers on. None of their internal ROM dumps (we have several now thanks to these dumps it seems) should have had that as it was made for non Nintendo emulators and holds little value for anything they would be doing.
You would be exceptionally hard pressed to have Nintendo (or their agents as I believe these were farmed out to third parties) found guilty of any kind of wrongdoing for that (the header part was probably unused in the emulator and I am not sure it rises to the level of copyrighted material/format), and as such it was more of an amusing curio and possibly insight into Nintendo's development culture (I have certainly been in places where expedience causes me to take somewhat dubious paths). At worst if Nintendo downloaded it from a torrent and seeded it then they would have that, and I am sure they are not going to sue themselves for damages they did to themselves.
Some non Nintendo devs also used public domain emulators on the GBA for some of their NES efforts (pocketnes was made public domain, not just share alike open source, and some other devs used that)
https://waxy.org/2004/07/jaleco_borrows/
Nintendo might also have been a bit reticent about sharing any changes/code for browsers and image viewers they might have used but as far as I am aware after some prodding usually made good there as well.
I forgot to mention this
How benefical are these "leaks" I thought we already have good up and running emulators for the N64. Android N64 emulator works amazing and so does PC. I honestly don't think this is really going to help make native ports because I doubt devs are going to be messing with legal code and etc risking a lawsuit. I also thought we already have N64 on retroarch it runs fairly decent so am I missing something here?
Also for the argument above yes if the switch was my only device I would feel duped too. The best thing I can say is just don't complain too much and just pirate all the games you can.
Emulators are nice and all but much like we saw (and saw predicted) for Mario 64 then this opens the doors to ports for other systems, radical hacks that would take skilled assembly hackers years to do rendered possibly by half bright kids that know their way around a compiler* doable in a few weekends, easier bugfixes and tweaks, ports to other systems also means widescreen, high res, better controls, easily remapped controls in game, stats tweaks, level editors now know exactly what the game will interpret as what without having to figure it out, and this goes on.
*or indeed just someone that can dead reckon something -- you might not be able to tell me what all the punctuation and whatnot means in a bit of C code (never mind if someone had some fun playing obfuscator) or what type declaration is but if you did a search in something for, say, gravity and somewhere in it the code said gravity =2.0 and you thought "what happens if I put 5.0 here", pressed compile and played the result, found you barely able to get off the floor and instead put 0.5 in then you now have moon gravity and Jupiter gravity hacks without having to step through a jump routine's assembly code and figure out what each minor step involves. Repeat for damage (to or from enemies), speed, possibly a godzilla size hack (look for scaling factors), default camera position/speed/acceleration (
https://docs.google.com/document/d/1iNSQIyNpVGHeak6isbP6AHdHD50gs8MNXF1GCf08efg/pub?embedded=true http://hciweb.usask.ca/uploads/332-aim-assist-cameraReady-v8-final.pdf ) maybe a decent leg up in figuring out a format to make an editor with, maybe hints of a hidden/undiscovered feature (
or final word on rumours about something being in a game) and it goes on and on and on.