How to get purchased apps list, including the prices? [duplicate]

Question

Background

I have a small app (here) for showing a list of apps.

Recently, I was informed that there is an app (here) that shows a list of purchased apps, including their prices.

I've tested it, and it indeed shows all of the purchased apps, just like on the Google Play website (here)

The problem and what I've found

I didn't even know it's possible to get such a list, so after I've searched the Internet, and here, I still don't get how this was done.

All I know is that this app uses some authentication from the user, to get the list of apps from his Google account.

And, all I've found is that there are some non-official libraries (most are very very old) to get information of apps from the Play Store, but nothing seems official.

The questions

1. What is the API that can be used to get information of purchased apps?

2. Can it do more ? Maybe perform search? Maybe show free apps that were installed? Maybe the time they were installed and uninstalled? And the categories of those apps?

3. Are there any special requirements for using this API ?

Answer 1

Because this question has a bounty, it doesn't let me point to the duplicate so I'll do it here.

It looks like there's a post that has as good an answer as you could get here.

The long and short of it seems to be that you'd want to request permission from Google (via GoogleSignIn). Then from the post:

If full access can be gained a list of all apps used by the account holder can be found and compared to what's on the device.

And then the answer goes onto cover how querying the packagemanager can get you access to the apps installed:

Package Manager will retrieve a list of all apps currently installed on the device. PackageInfo provides the details about the app. INSTALL_REASON_USER will also filter out apps that have been actively installed by the user.

You might want to look at com.google.firebase.appindexing and Log User Actions. Different actions can be tracked.

The users account history is found at https://myactivity.google.com/myactivity.

A helpful link is the OAuth 2.0 Playground.

I'd highly recommend continuing any conversation on that thread, as it seems to be more active and have more upvotes.