More attacks by dump AI-bots

[Achim D. Brucker]

>>    https://isabelle.sketis.net/components
>>    https://isabelle.sketis.net/repos/isabelle
>>    https://isabelle.sketis.net/repos/isabelle-release
> The problem are our hgweb servers (via Apache and its builtin Python 
> engine), this also applies to https://isabelle.in.tum.de/repos which 
> is presently unusable.
> We need to find a proper solution for hgweb + Apache specifically.

I would not call it a "proper" solution, but I am currently using Anubis 
(https://anubis.techaro.lol/) with quite some success. Of course, it's 
an arms race - computing the challenges set out by it are not that 
expensive. Hence, when enough website use it, the crawlers will 
implement the challenge solving part ...


Achim