Show  me a mod tools that make you change the game code of a closed code game...

Wikipedia is wrong... a better and simple description.

"The term mod is derived from the act of modifying a game. To mod a game is to create custom levels, objects, characters, or even unique or stand-alone game from an existing game engine. Many games come with an editor that allow for easier modding. A person who mods a game is called a modder."

You can in fact change your own mod code (maybe the Wiki program code means your own mod) but not the game code (only devs can do that).

PS. I will submit a change to Wiki later if I have time.

Just to be clear... if you have access to the source code of a program or game then you are changing the program in the best way possible and not modding... you can release a patch, or your own version of the game (fork), etc.

Moding means that you are changing the game without change the Engine (Game) source code.

I know WIndows 8 metro doesn't support XNA. Can I make XBoxOne games with Visual Studio and XNA? I don't need more resources than a small indie game needs.

I think you might be jumping to conclusions about what Microsoft is going to allow. The Xbox environment isn't exactly known for being open. My guess is that mods are going to have to submitted and approved from the developer's side, after they've made sure they work. Look at the certification process they have to go through for patches, I can't imagine they'll let through hundreds of poorly written mods, some of which will almost certainly be malicious in nature.

This isn't going to be like the PC, I'm almost positive.

They retired XNA, hence no windows 8 support. The dev kit abilities of the xbox one are filling in as its replacement. I'm not sure of the specifics for coding(it's not out yet ;) but yeah you'd be able to make a game with free software. You can also make a Wii, Wii U, 360, PS3, or PS4 indie game with free software. The publishing and licensing costs are the big expenses for indies. They're what really matter.

Am I right that when they say one can "self-publish" a game on a particular platform, they mean no licensing/publishing fees?

I've never really been a fan of mods. I'd rather just play the game the way the developers intended me to.

I would love to be able to mod console games! I know Skyrim has an awesome community for modding, as well as other popular console titles. I just hope that the companies that do support modding will support it in such a way to prevent modded cheats for the base game experience. X1 is looking more and more like a programmers / indie devs wet dream of a console.

-edit- @ethomaz

Wikipedia is not a reputable source for information at all. If I ever see something being quoted from Wiki I skip over it as its not a reputable source. The only time I use it is to find quick information and their sources for stuff that it wouldn't matter if the info was correct or not.