somehow related...
It's curious because this permission also suddenly appeared in one of my apps, not being aware of having changed anything (well, sure I did, perhaps my XCode version, also local builder, and making different uses of the existing libs, but not adding new ones) I'd even say that sometimes it appeared and sometimes not
P.S. If the URL is on the Internet like
https://www.mydomain.com - no questions asked and it works by itself.
If the URL is on my local network - I have this problem. But this question asked if I use HttpJob PostString. If I use HttpJob DownloadString with the same URL - no questions asked.
This would explain several things (not the fact that it only happens with poststring, but that it appears when communicating with local URLs).
in my case I have several frameworks which communicate in background so I guess that 'from time to time' one of them does something that is 'local' (even if it should not)