Guidelines for greeter-like windows
I've started (re)writing an app that manages presentations. Users need to either select an existing presentation, or create a new one, when opening the app.
In the past we used to have 2 design patterns that, together, covered this use case: initial setup; and the welcome state for content apps.
Nowadays, it is unclear (to me) how greeters should look like; how they should present the selectable content; how they should greet and perform the initial setup of the app; and when they should and shouldn't be used.
For reference, GNOME Builder is an app that has a greeter: