"Third Parties. We work with third parties to provide some of our Services. For example, our Third-Party Providers send a verification code to your phone number when you register for our Services. These providers are bound by their Privacy Policies to safeguard that information. If you use other Third-Party Services like YouTube, Spotify, Giphy, etc. in connection with our Services, their Terms and Privacy Policies govern your use of those services."
We work with third parties to provide some of our Services.
What type of Services? And do Signal use our contacts or something private like that for third-parties?
It does offer an example of the services they use third parties to provide in the next sentence. So they're obviously giving out the phone number you provided at sign-up to the verification code people. I don't think there's any reason to believe they're giving away your contact list from this paragraph anyway.
It has end-to-end encryption for messages and its clear. But, I haven't looked at their source code yet and don't know which types data they send. Not only contacts, maybe more spesific things that is not encrypted. Just wanted to know it. But its exact that they give our numbers for verification. Thanks for comment. Goodbye.