What's the default Python version in Ubuntu 20.04?
Ubuntu 20.04 has Python 3.8.2 as the default version. Officilal Release Notes about Python
According to the Ubuntu 20.04 release notes:
Ubuntu 20.04 LTS comes with a refreshed state-of-the-art toolchain including new upstream releases of glibc 2.31, OpenJDK 11, rustc 1.41, GCC 9.3, Python 3.8.2, ruby 2.7.0, php 7.4, perl 5.30 and golang 1.13.
Manifest file
Another thing you can do for any Ubuntu version and any package is to check the manifest file which lists all preinstalled packages in the image: https://web.archive.org/web/20200508223720/https://releases.ubuntu.com/20.04/ubuntu-20.04-desktop-amd64.manifest
It contains python3.8
but nothing that seems python2 related.
See also: How do I list the default installed packages?