How to check cygwin version?

[Jeffrey Walton]

I think the documentation leaves a lot to be desired... I'm trying to
tell someone what version of Cygwin I am using.

There's a FAQ item at
https://cygwin.com/faq/faq.html#faq.what.version. It gives this
useless advice:

   To find the version of the Cygwin DLL installed, you can use uname
   as on Linux or cygcheck. Refer to each command's --help output and
   the Cygwin User's Guide for more information.

OK, let's try it:

$ cygcheck -v
Usage: cygcheck [-v] [-h] PROGRAM
       cygcheck -c [-d] [PACKAGE]
       cygcheck -s [-r] [-v] [-h]
       cygcheck -k
       ...

OK, -v is what we need:

$ cygcheck -v cygwin
cygcheck: could not find 'cygwin'

OK, another failure.

RTFM does not work. Why the hell don't you just state how to check the
god damn version?