Yes, it is a recent change. Before, the v2 header was necessary for these endpoints, but now they are part of the regular Postman API.
The /apis endpoints are the https://api.getpostman.com/apis endpoints. Endpoints to manage your APIs via the Postman API (Postman). If you take a look at that documentation, you’ll see two folders in the collection: v9 and v10. The v10 header is necessary for the v10 endpoints.