Where can I find information on the Android permission system device?

Question

Android

Where can I find detailed information about android device permissions? Are there articles where you can read the essence of each specific permissions and their features (and pitfalls)? Preferably not very technical articles.
Interested in the moment related to privacy. Here are some examples:
1) Access to external storage. In the bugaevc article -a it is written that access to external storage (sometimes it is an SD card, sometimes just a separate space of internal memory) can not be given to almost any application (except for the file manager), because even without this permission, applications have access to their folder in external storage. And indeed, after I restricted access to all my applications, almost all of these applications continued to work, except for one. For some, the cache of pictures and textures was reset, but then everything was pumped up (apparently now in their folder). Why then do almost all applications ask for access to external storage?
2) have full network access - nothing at all is clear with this permission. Somewhere it is written that this absence of this permission does not mean that the application does not have access to the Internet, but if there is this permission, then there will definitely be access. It is not clear, it turns out that there are overlapping permissions? Or by default, each application has access to the Internet.
Also, in addition to accessing the Internet, I noticed that an application that has such permission has access to information with which IPs other applications communicate. I installed a special application Net Monitor (by secuso) which had only one permission "have full network access" and it sees which application is connected to which IP on which protocol. I have lineageos 15 (android 8.1) and additionally have AppOpsx and afwall+ programs. So I limited this application to all accesses without exceptions wherever possible. And still Net Monitor sees all other people's connections. Why? Is there a way to restrict access to such data applications, while leaving them access to the Internet.
3) Somewhere I read information that with the release of each new version of Android (and API level, respectively), Google adds granularity to permissions, but it happens that until the application is recompiled by the developer under the new version of the API, it will ignore granularity and get more rights. I also recall some other similar facts, in which Google tried to force the developer to granulate permissions, but he managed to do it with difficulty. Where can I read about all this?
This is just an example, other pitfalls are possible, everything that is related to security and privacy is of interest.

Answer 1

https://developer.android.com/guide/topics/permiss...
https://developer.android.com/reference/android/Ma...