Source: Schema.org v30.1 vocabulary. Official guidelineDate property definition.
What does guidelineDate mean?
Date on which this guideline's recommendation was made.
Used on types (domainIncludes)
Expected value types (rangeIncludes)
Schema.org domainIncludes and rangeIncludes are descriptive guidance, not strict validation prohibitions. Check the official reference for updates.
Related reference
Browse all Schema.org types and properties · Google feature support status