Data & schema semantics
· Type system
x-extensible-enum
`x-extensible-enum` appears on schema objects and properties. Its value is a list. Used by 13 providers across 21 OpenAPI documents. Consistent with type system — this is inferred from where the key appears and what it carries, not from any published definition.
Data & schema semantics
derived description
How this description was produced. It is assembled from what was
measured in the corpus — where this key appears in a document, what shape its value
takes, the values observed, and how many providers use it. It is not taken
from a published definition, because for most extensions none exists. Read it as
evidence, not as a specification. If you own this extension and want it described
properly, tell us.
147 occurrences
21 documents
13 providers
purpose-named
Where it appears
| Location in the document | Occurrences | |
|---|---|---|
| schema | 146 | |
| parameter | 1 |
What its value looks like
| Value shape | Occurrences |
|---|---|
| array | 147 |
Providers publishing it
All 13.
aarhuscityueindhoven-university-of-technologyhong-kong-baptist-universityinterhypkfupmqueens-university-belfastuniversity-of-bathuniversity-of-groningenvrije-universiteit-amsterdamyonseizalandozally
Why this is not in OpenAPI
Extensions exist because a provider needed something the specification would not carry. Most of what they hold is not the API contract at all — it is operational metadata about the contract: documentation, lifecycle, policy, provenance, and now agents. That metadata is usually better placed alongside the contract, in an Overlay or an APIs.json index, than crammed inside it. See everything else doing the data & schema semantics job.