The WordPress Codex has been a great resource for developers around the world and has long resided at: 1)codex.wordpress.org
However…. In the modern era, this resource has been expanded and migrated over to: 2)developer.wordpress.org/reference
Within the realm of comments, there are literally hundreds of different topic areas with great reference material about WordPress comments. These include things like:
3)developer.wordpress.org/?s=WP_Comment
So, whether you’re looking to get comments, filter, manipulate, modify, display, delete or otherwise programmatically work with comments in WordPress - as a developer, the new Codex home is a great place to begin: 4)developer.wordpress.org/reference