Hi we have example repos on the website, you can see the link for use cases for oas specs in the table
https://docs.pactflow.io/docs/examples#providers
From the provider side, the provider would provide their own functional testing against their oas spec and service, the results of which are uploaded to Pactflow along with the oas spec.
The validation in Pactflow will take place against the uploaded oas spec and a consumers pact file when they call can-i-deploy to ensure that the consumers pacts are valid against the oas spec against whichever environment the consumer is targeting.