Ah yes, the language where a string can magically become a boolean and cause an error. And you can never be sure what is legal because of so many changes in parsing legality between versions.
Prior to YAML 1.2, unquoted numeric values containing : were interpreted as base 60, a common trip-up for Docker Compose port mappings. The intent was to make it easier to write times, i.e., 2:00 == 120.
Yaml is one of the worst config languages.