Comment 8 for bug 1772448

The shell script checks for the existence of /usr/bin/python3, so it will fail gracefully if python3 is not installed. Not sure what the intent of that was (python3 not widely available at the time this was written, maybe?), but for now let's keep the test and not add an explicit runtime dependency. I think it can be safely assumed that python3 will be installed anyway on most modern distributions.