Learning YAML
A very nice introduction to YAML by Maria Marshmallow can be found at dev.to
Comments
Comments are very helpful, since it mean that you can hide something from machine use/interpretation and you can annotate your public parts for human interpretation.
YAML only supports single lines comments. Comments are prefixed with: #
# This is a comment
Comments can also be appended to YAML lines
key: value # this is the key and it's value
TODO more to come