GitHub’s permission scopes and GitLabs authentication don't allow us to specify fine-grained read/write permissions, so we require read/write for your entire repo. 

Write access to your repo allows us to create a webhook that notifies us of relevant events (i.e., push events, new branches, merges, etc). It also allows us to post comments on commits.

We know how important it is to you to keep your code safe - we want the same for our own. Our reputation is dependent on your trust, and we strive for complete transparency. We will never change your source code.