Are you still running into this? That is really strange, since you’re right that we don’t support 3.6. It looks like your runtime.txt used to say 3.6, so I’m wondering if there was a cache issue at some point. I think our next suggestion would be to check your buildhtml.sh file and if that’s what pulls the Python version, locally print the Python version that it finds and confirm that it is 3.5. If it is, then my next suggestion would be to deploy with the “Clear cache and deploy site” button:
Do you want to give those a shot and let us know how they go?
2:12:03 AM: Preparing Git Reference refs/heads/master
2:12:03 AM: Starting build script
2:12:03 AM: Installing dependencies
2:12:03 AM: /usr/local/bin/run-build-functions.sh: line 170: /opt/buildhome/pythonpython-3.6.9/bin/activate: No such file or directory
2:12:03 AM: Error setting python version from runtime.txt
2:12:03 AM: Please see https://github.com/netlify/build-image/#included-software for current versions
Am using vuepress for the docs and it has nothing do with the python part of the project.