RoboFont is designed around a model where most actions – such as opening a font, typing a keystroke, toggling on a glyph preview, etc. – will all broadcast “notifications” to any Python script that wants to listen in.
This system of notifications is what makes more complex extensions possible. They’re also handy to add your own “preferences” to RoboFont, adding features that the application developer couldn’t have anticipated someone else needing.
By running the Event Observer extension you can see all of the notifications flooding in as you work – opening a new font might trigger more than 10 notifications for each action that takes place behind the scenes.