2) Use properties to describe since and description
We can still use !deprecated tag for marking the file as deprecated but the information of it will be stored in plain YAML properties like the following:
!deprecated mgnl:deprecatedSince: 5.6 mgnl:deprecatedReason: Some reason
Or without the tag we could simply have it like:
mgnl:deprecated: since: 5.6 description: some_reason
In the end we have decided to go with approach 2.b. This is due to the fact that It is a no-go to have description written without spaces, we simply can't ask that from customer or even from our devs. Also everything related to deprecation information is now in one place (node) and properties and are sub-properties of the node.