[Android Q&A, Help & Troubleshooting] GalaxyA325G:
Thank you for your observations so that I know it's not just me who has this huge privacy hole that I didn't even know existed!

I love that you volunteered additional useful details that will help me debug (and which should help everyone - which is always the point of posting) where your setup is different from mine (for example, you have the phone registered to a Google Account, I don't - and yet you saw the same Firebase App Indexing that I did).

Keep in mind that I go out of my way to NOT set a Google Account on the phone (so that Google can't save anything to that non-existing account), and therefore I NEVER sign into any Google app which "asks for" a signin (e.g., Google Maps, the GMail App, Google Voice, YouTube, Google Play, etc.).

The instant you sign in to some of those (GMail & Google Voice for example), the mere act of signing into a Google account will automatically CREATE a Google Account on the phone. So my rule is never sign into anything on the phone (hence I have no accounts set up on the phone - and it works just fine without them).

However, I do use the Google Maps app (without signing into it), where you can see in my tests listed in the OP, I searched for "100 Main Street" which was captured in the Firebase App Indexing in gory detail.

Luckily nothing was "transmitted" but every destination I ever entered into the Google Maps app was stored on the phone, where the question now is how to wipe out all that stored Firebase app indexing data, en masse?

From the standpoint of privacy, it's terrible these Android Firebase App Indexes exist, and worse, it's horrid that we don't know (yet) how to easily clear them (as they contain ALL your Google Map searches, even if you've never once ever logged into any Google Account!).

I don't have a Google Account (for privacy) but I can't root my phone yet (as T-Mobile owns it for another year and a half) so I'm stuck with just disabling what seem to be non essential Google packages.

What surprised me is that I don't have an account when I use Google Maps so I was surprised that the phone saved the search locations in the Firebase.

Looking for how that could be possible, I noticed this isn't disabled.

Google Location History (com.google.android.gms.location.history)

Looking in my free ad free App Manager, I see that Google Location History hasn't

transmitted

any data but it did

store

32.77kB of data.

Maybe that's how Google Map searches end up in the Firebase?

To test, I just did the following (wish me luck) hoping it might clear those Google Map destination searches from the Android Firebase privacy hole.

Android 11: Settings

Apps

Your apps

(with "Show system apps === on")

Google Location History

App info

Google Location History

(with "Permissions === No permissions allowed")

[access location in the background]

[access precise location only in the foreground]

[access approximate location only in the foreground]

(with "Location === Denied")

(with "Set as default === Not set as default")

Usage > Mobile data > Total = 0 B

(Allow background data usage === I turned this off)

(Allow data usage while Data saver is on === off)

Usage > Storage > Total = 32.77 KB

(App === 32.77 KB

(Data === 0 B)

(Cache === 0 B)

Unfortunately the "Clear cache" & "Clear data" buttons on the bottom were both grayed out

So how are you supposed to clear that app data?

After doing that, I then purposefully borked Google Location History as best I could as shown below (some of the steps are similar).

Android 11: Settings

Apps

Your apps

(with "Show system apps === on")

Google Location History

App info

Google Location History

(with "Permissions === No permissions allowed")

(with "Location === Denied")

(with "Set as default === Not set as default")

Force stop

You can't "Uninstall" because it's a protected system app)

You can't "Disable" either for the same reason.

(Disable is grayed out)

Be careful when you force stop a protected system app because the force-stopped app (in this case, Google Location History) will suddenly completely disappear from your phone (AFAICT) such that it won't appear in a search inside most app drawer apps, and it won't show up in most app managers.

From experience, I know that my FOSS App Manager shows stopped/disabled systems apps but others might not be aware of this caveat. In that App Manager, when you tap on "Google Location History", you can hit the threedots at the top right and then click "View in Settings" which will bring you to the Android settings for that app, even as after you force stop the system app, you can no longer get to those Android settings for that app through the normal Android methods anymore.

Notice what I just said, which is once a system app like Google Location History is disabled/stopped, you can no longer FIND it in the Android Settings to turn it on, and even if you did find it (like I show above using my FOSS App Manager, you still can't re-enable it until you know how to do that - which I describe below for clarity).

Start the FOSS App Manager

Run a search for "google" to find "Google Location History"

Long press on the result to select "Google Location History"

Press the threedots (at the bottom right) of the selected set

Your choices for "Google Location History" will be

Uninstall

Enable

Disable

Force-stop

Clear Data

Save APK

Backup/Restore

Prevent background operation

Block/unblock trackers

Export Blocking Rules

Add to profile

You should be able to select the "Enable" option.