where is private key of subscription v2, i find everywhere.buy still print "crypto/ecdsa: verification error"
where is private key of subscription v2
If you are talking about the App Store Server APIs, as described here https://developer.apple.com/documentation/appstoreserverapi, https://developer.apple.com/documentation/appstoreserverapi/creating_api_keys_to_use_with_the_app_store_server_api describes how to create these API keys.
I am guessing you are referring Server notification v2 that are JWS transactions. The private key for any party will/should never be published but maybe you are looking for a public key to verify the authenticity of the signed transaction? If so, maybe this is what you are looking for: https://www.apple.com/certificateauthority/