How do I add a favicon that only shows during viewing of my plugin's admin panel? I mean, what event do I intercept?
When you add your admin (sub)page, then you're (hopfully) using
Then you can simply add your callback (that adds the favicon) to the
Edit: To get better an insights and to "proof", that this hook actually exists, you can use my »current admin info« plugin, which you can download on GitHub. It shows you which globals are set, as well as which contextual hooks are available and what their names are, on the admin page you're currently viewing.
Here's how you'd do it in a procedural way. Inside an OOP architectured piece of code, you'd probably save it into a class var and then use this var to add your favicon action/callback.
You can add this to your functions.php file and or make a plugin out of it.