YAML stands for “YAML Ain’t Markup Language”, (originally “Yet Another Markup Language”).
It it a way of storing the same kind of thing that JSON can store.
Though, unlike JSON, it supports comments, uses a python-like significant indentation, and has a few uh, things not in quotes sometimes being taken as strings, but if it is `NO` then instead, if there are no quotes, it will be interpreted as the constant false .
Which I think drives the point of all this crypto talk in acronyms contributes to it being incomprehensible.