bug#25548: 25.1; Wrong Emacs version for Emacs 25.1.2 (?)

[Drew Adams <drew.adams@oracle.com>]

> > This is the zip file I picked up:
> > emacs-25.1-2-x86_64-w64-mingw32.zip     29-Nov-2016 14:12   91M
> > But when I open Emacs and use M-x emacs-version it tells me that it is
> > Emacs 21.1.1.  And you can see that below, as well.
> >
> > What gives?  Is this correct or a bug?  How are users supposed to
> > understand the version numbering - is this 25.1.1 or 25.1.2 or
> > something else?
> 
> It's 25.1-2, that is a second release of version 25.1. The first one
> was compiled without optimization.
> https://lists.gnu.org/archive/html/emacs-devel/2016-11/msg00293.html

Sorry, but I still don't understand.  What's the difference between
25.1-2 and 25.1.2?  Do both 25.1-1 (whatever/wherever that is) and
25.1-2 correspond to 25.1.1?

Where does a user see the version number 25.1-2 (or whatever kind of
number it is, if it is not a version number)?  How, from Emacs itself,
does a user tell the difference between 25.1-1 and 25.1-2?

These were the zip files downloaded, respectively:

 emacs-25.1-x86_64-mingw32.zip
 emacs-25.1-2-x86_64-w64-mingw32.zip

What does a user (or code) look for within Emacs, to tell the difference?

And are these releases?  Release candidates?  Pretest builds?  How to know?

Is all this supposed to be clear to users?  Where do they learn about
such nomenclature (zip and release)?  At the mirrors where you download
these things there is no description/explanation.  (They don't even tell
you what the difference is between zips x86 and i86.)

I realize that building and uploading Emacs for Windows is a volunteer
effort, and I'm grateful for it.  But can we perhaps make the zip naming
clearer?  (I'm guessing at this point that there might not be any
Emacs-detectable version difference, in spite of the zip name difference.)