Python 3 was introduced back in 2008, and the transition period for distributions to maintain two incompatible Python versions has come to an end, with support for Python 2 ending on December 31, 2019. Already in 2014, Python project leader Guido van Rossum had extended the support for Python 2.7 to 2020, declaring that this is the latest release in the Python 2 cycle. So it’s high time to migrate packages based on Python 2 to the successor.
Debian and Ubuntu also see it that way. After all, Ubuntu first wanted to declare version 14.04 Python 3 as standard. Debian 10 will continue to support Python 2 until the end of support for Buster. For Canonical, this applies to the lifetime of Ubuntu 18.04 »Bionic Beaver« LTS, ie until 2023. Both projects want to stop using Debian 11 “Bullseye” respectively Ubuntu 20.04 LTS their support of Python 2.
Submitted by: Arnfried Walbrecht