OpenGL registry????

please reply to this
i found OpenGL registry while i am surfing

and on clicking at GL_BLA_abc_xyz

a text file open

where
BLA_abc_xyz
list ofname of some people

and look like long file

and some OpenGL function name
and a OpenGL’s glFunctionNameEXT/ARB
written

Q1is use of these function our experiment(may damage system)
Q2 i have find that most api have Docs/mannual almost those of Open
is there a way Just read Docs/specs and hit up the floor
Q3.is there need a lot of practise on these function so tha
get one working(cause all tutorial i found only checks availability of Extension not their function are used)

(i hope it not waste your time & alot of thank for just reading my post and also for thinking on my Q)

The GL registry is at http://www.opengl.org/registry
You can access it if you look at the top of this page where it says Documentation.
There is also the specification page.

Q1. No, it won’t damage your system. What are you worried about?
Q2. I’m not sure what you mean.
Q3. Yes.

What extension are you talking about?

Q2 is docs/specs/mannual are best way in programming in any API???

Depends on the quality of documents. A good document should be articulate and address basic issues that a first time user may face.

It includes restrictions and language capabilities and most importantly, well illustrated.

you should get familiar with extensions in general: http://www.opengl.org/wiki/OpenGL_extensions