When I actually googled SRAM Eagle to see how confusing it all was .... I got this:
So not only was there SRAM's corporate hype, there were several specific questions, and an independent review. No one who made much effort would be confused.
Pete Hski replied, "Eagle is just a collective name for all SRAM 12 speed mtb groupsets. It gives a very wide range across 12 cassette gears." and that was enough to satisfy the OP. Seems that all that info was available on the search page ....
Me, I do so basic research and then ask specific questions if I need more explanation. But that's just me.
Hopefully, in future the poster will ask more specific questions so that people can better answer his questions.
I do notice that after one response suggesting googling it, the poster started slinging curses around.
Maybe a better second post would have been, "Thanks, I went to the SRAM site but didn't understand these specific points .... " but again, what do I know? Just because those approaches work for me, no reason to think they work generally.