What is the primary purpose of the "Client Secret" in the OAuth 2.0 authentication process?

The primary purpose of the "Client Secret" in the OAuth 2.0 authentication process is to verify the identity of the client application requesting access to a user's data. It functions like a password that only the client application and the authorization server know.

The client credentials as well as any access token issued to the client are stored on the web server and are not exposed to or accessible by the resource owner.