This may be a little off-topic, but could you give me some examples of what a Jupyter Server Extension would be or look like?
Sure. Jupyter Server Extensions just append new URL endpoints+handlers to the Jupyter Server.
Two examples of jupyter server extensions (there are many more) are:
JupyterLab-git: “emitting” events from this extension requires jupyterlab-git to be made aware of the telemetry system.
Developers of server extensions may want to add their extension (i.e. emit events) to the telemetry system. They will have to add logic to emit events from their extension.
JupyterHub Service similar in any way to a Jupyter X Extension
Yep, JupyterHub Services are essentially JupyterHub “extensions”. I’m speculating here but I believe we call them services because JupyterHub doesn’t really behave like a single server that’s being extended. Rather, it’s behaves like a gatekeeper for a collection of separate services. Creating a JupyterHub Service is just adding another member to the collection.
Although, you’ll have to ask someone who’s been around longer than me to verify my spec