x-summary-i18n

`x-summary-i18n` appears on operations. Its value is a structured object. Used by a single provider across 6 OpenAPI documents. Consistent with documentation & dx — this is inferred from where the key appears and what it carries, not from any published definition.

Documentation & DX 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.
135 occurrences
6 documents
1 providers
purpose-named

Where it appears

Location in the documentOccurrences
operation 106
response 4
components 25

What its value looks like

Value shapeOccurrences
object135

Providers publishing it

All 1.

raiffeisen-ru

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 documentation & dx job.