This is a HTTP server that allow a YunoHost instance to check if it can be reached by HTTP from outside before trying to generate a LE certificate.
This is done because some network configration prevent HTTP loopback.
This is a trivial python 3 (yes 3) project to install, juste create a
virtualenv, install the content of the requirements.txt (there is a "-frozen"
version if need) and do python server.py. No other configuration/db needed.