Hi,
This was raised in https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1077184 exactly 2 days after the changed was merged.
Still, package maintainer didn't listen that this symlink removal really broke everything. Without net.ipv4.ip_forward=1 from this file, a whole network was down.
So, NEWS file is empty, and therefore, no mention of this in release notes: https://www.debian.org/releases/trixie/release-notes/search.html?q=sysctl.conf&check_keywords=yes&area=default
I'm glad that I'm not the only one, but I'm sad that this *really important disruptive* change was made completely silent.
Adrien