bug#37414: 26.3; (emacs) `Contributing': no `etc/CONTRIBUTE'

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

(emacs) `Contributing' says:

  For more information on how to contribute, see the 'etc/CONTRIBUTE'
  file in the Emacs distribution.

I find no such file.  I'm using ordinary Emacs releases on MS Windows.

First, there are two `etc' folders: One at the top level of the zip
archive, and one as folder `share/emacs/26.3/etc'.  So those
instructions about looking for `etc/CONTRIBUTE' aren't clear.

I find no `CONTRIBUTE' in either of those `etc' folders.  Searching with
Windows Explorer finds no such file anywhere in the Emacs 26.3
distribution (I have the "full" distribution, i.e., with dependencies).

I find file `share/emacs/26.3/etc/README', but that says almost nothing,
and certainly nothing about contributing to Emacs development.  I also
find `share/emacs/26.3/README.W32', but that makes no reference to
`CONTRIBUTE'.

When I search the distribution of Emacs 24.5, I find CONTRIBUTE in
folder `share/emacs/24.5/etc'.  Similarly for some other releases (for
23.4 it is in top-level folder `etc'; for 22.3 it's in the top-level
folder).  But starting with Emacs 25.3.1 I find no such file.  (I also
find no such file for 21.4 or 20.7.)

What am I missing?  Where is a user on MS Windows supposed to find file
`CONTRIBUTE'?

In GNU Emacs 26.3 (build 1, x86_64-w64-mingw32)
 of 2019-08-29
Repository revision: 96dd0196c28bc36779584e47fffcca433c9309cd
Windowing system distributor `Microsoft Corp.', version 10.0.17763
Configured using:
 `configure --without-dbus --host=x86_64-w64-mingw32
 --without-compress-install 'CFLAGS=-O2 -static -g3''