Limited YAML map keys to strings

Author: darrelmiller

versions/3.0.md

@@ -70,7 +70,7 @@ The schema exposes two types of fields. Fixed fields, which have a declared name
 In order to preserve the ability to round-trip between YAML and JSON formats, YAML version [1.2](http://www.yaml.org/spec/1.2/spec.html) is recommended along with some additional constraints:
 
 - Tags MUST be limited to those allowed by the [JSON Schema ruleset](http://www.yaml.org/spec/1.2/spec.html#id2803231)
-- Keys used in YAML maps MUST be limited to scalars defined by the JSON schema ruleset
+- Keys used in YAML maps MUST be limited to a scalar string, as defined by the YAML Failsafe schema ruleset
 
 ### File Structure