The devs of Little Snitch came up with a convention to annotate network traffic, so to speak. It's called "Internet Access Policy" and will show the purpose of your app establishing a connection in Little Snitch's warning dialogs.
It is implemented by adding a
InternetAccessPolicy.plist to the app bundle with a dictionary of connection details. This could potentially be used by other 3rd party firewalls as well. That's what I like most about it: it provides useful information to end users without locking developers into anything. A Property List is innocent enough and could potentially spawn other uses.
Look at the project website to see how many of the big names have added IAP's to their apps already, plus yours truly: Acorn, BBEdit, MindNode, Ulysses, Paw – and many others.
This reminds me of a time 10 years ago when macOS didn't support tagging of files, yet, and the OpenMeta tagging convention was introduced by indie devs and became a roaring success with various productivity apps.