Comment 19 for bug 1735363

The problem is that in the Linux world there is no real, final, decision on what to do with the name "python". So, at least in Debian/Ubuntu, we have no plans on having /usr/bin/python to ever
 point to anything that is not Python 2. In Arch Linux, the situation is the opposite instead…

There is https://www.python.org/dev/peps/pep-0394/ that tried to reach a conclusion, but it actually caused even more confusion, so the world is all in flux.

Having said that, if you explicitly write "python3" you are quite sure it will be run under python3, so it's generally a good idea, IMHO.

If there really are shebangs or calls to python instead of python3, but the targets are compatible, then the distributions can patch those to python3 as needed without much trouble anyway, so, for now, we can consider this issue over. Later, in a few years, once the situation on the interpreter name stabilizes, this choice can be reviewed.