GMP website: old release (3.1.1) cannot be downloaded

[Hans Åberg]

> On 26 Dec 2020, at 09:33, Niels Möller <nisse at lysator.liu.se> wrote:
> 
> "Peter Jin" <peter at appliedpataphysics.com> writes:
> 
>> 1. Go to https://gmplib.org/download/gmp/archive/
>> 2. Try to download either "gmp-3.1.1.tar.bz2" or "gmp-3.1.1.tar.xz"
>> 3. Response: HTTP/2 403 Forbidden (server: nginx/1.18.0, etc.)
> 
> Going to that directory listing page (I'm using firefox, no idea if it
> attempts to use HTTP/2) and clicking those links works for me. Maybe
> some temporary error? If problem persists, you'd need to share more
> details on what tools you use to download.

It works now, but not before, using Safari on MacOS 11. Note though that there are duplicate URLs; on the first, it worked, the error was on the second:
https://gmplib.org/download/archive/
https://gmplib.org/download/gmp/archive/