Package: src:ifupdown2 Version: 1.2.5-1 Severity: important Python2.7 will go out of upstream security support during the Bullseye development cycle. It is not safe to assume it will be included in the next release, so if you want to be sure ifupdown2 can stay in Debian, please port it to python3.
Personally, I want to remove some packages I maintain, particularly python- ipaddr, which ifupdown2 depends on during the Bullseye cycle, regardless of what happens to python2.7, so please update (python3 includes the ipaddress module, which was developed from ipaddr, in the standard library).