bug#53202: 27.2; Shift + function key not recognized

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

Feel free to rename this bug report as appropriate.

And I'm not sure if it should be a report about missing doc (or doc I
didn't fine) or a report about bugged behavior.  I'm hoping that what I
don't understand is in fact documented, and I just didn't find that
doc.

emacs -Q

(global-set-key (kbd "S-<f10>") 'forward-char)

C-h w forward-char  ; Says it's bound to <S-f10>

But Emacs doesn't recognize that key at all.  E.g. `C-h k' followed by
Shift with function-key <f10>: the key isn't recognized.

I looked in the Emacs and Elisp manuals, checking index entries that
have "shift" or "function key" in them, but I didn't notice anything
that explained why that key isn't recognized.

But if I do the same thing with (kbd "S-<f3>") there's no such problem.

Is this a product bug?  A doc bug?  Neither?  Is it perhaps
platform-dependent?  I see this behavior also in older Emacs releases,
so it's not new.

In GNU Emacs 27.2 (build 1, x86_64-w64-mingw32)
 of 2021-03-26 built on CIRROCUMULUS
Repository revision: deef5efafb70f4b171265b896505b92b6eef24e6
Repository branch: HEAD
Windowing system distributor 'Microsoft Corp.', version 10.0.19042
System Description: Microsoft Windows 10 Pro (v10.0.2009.19042.1348)