Data & schema semantics

x-standard

`x-standard` appears in the info block. Its value is a string. Used by 3 providers across 4 OpenAPI documents. Observed values include `https://www.openarchives.org/OAI/openarchivesprotocol.html`, `FDX`. Consistent with data & schema semantics — 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.
4 occurrences
4 documents
3 providers
purpose-named

Where it appears

Location in the documentOccurrences
info 4

What its value looks like

Value shapeOccurrences
object1
string3

Observed values

Sampled from the specifications, most frequent first.

https://www.openarchives.org/OAI/openarchivesprotocol.htmlFDX

Providers publishing it

All 3.

anuregions-financialuniversity-of-oxford

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.