Implementation - Schema - Booleans
How many values are loaded as booleans in YAML 1.1?
  true  | True  | TRUE
| false | False | FALSE
| y | Y | yes | Yes | YES
| n | N | no  | No  | NO
| on  | On  | ON
| off | Off | OFF
22!
A classic gotcha is that the country code for Norway ('NO') loads as a boolean.