No google-services.json but still fetching the remote config from my Firebase project

I was trying to change google-services.json file of new project from old one. So, I deleted the old one and pasted new json file in two places one by one to test.

app/
app/src

1 case didn't work, so, tried 2 case. But didn't work either. Both cases fetch config from the old project.

So, I deleted app completely in the project. And then tried. Still working!

And then, I deleted all google-services.json files in my laptop. And then tried. BUT STILL WORKING.

How can I solve this problem?

Why do I need Google services json?

What it does. So this plugin and JSON file are not essential to running or publishing your app, it is just a quickstart helper to generate some basic android-resource files for easier integration of specific Google API features.

Where is Google services json in APK?

The google-services. json file is generally placed in the app/ directory (at the root of the Android Studio app module).

Invalidate cache & Restart Android Studio

OR

Delete app/build Directory from explorer or finder & Rebuild Project