OpenAPI 3.0 version for Webhook v2

Good morning!
Where can I download the OpenAPI 3.0 (Swagger) specification for Webhook v2?

I tried downloading it from the REST API Guide page, but the link points to version 1.6.2. I also tried using version 1.6.2, however the objects in this specification differ from those described in the manual (for example, TransactionDetails).

I also tried using the specification from GitHub, but the result is the same — the objects are different.

Many thanks!