Hi, probably a bit misleading word model was used here.
The general idea is to give an extension author API to register permissions presets for the records he provides.
So for example as an author of a News extension, you will be able to define like 2-3 (or more if needed) permission presets, for example: basic, advanced, full. This is just an example, the API will allow to define human-readable names for them with translation support etc.
Those presets will be listed in the backend group form, where you can click and apply some of them to the given group. So you don’t have to go through various permission sections and check multiple checkboxes etc. Instead by using a preset, all the checkboxes related to the given preset will be checked. You can then uncheck some or check more if needed.
So we do not talk here about frontend and the extbase models, but TCA and what you will see in the backend forms.
If you have more questions, please ask 
When we were starting work on the ACL improvements plan, I have created this diagram.
We are now talking about the Permission Preset box (to give you a wider overview).
