Tools to mod apk files

I wanted to compile a list of tools, for my own benefit. Here are 2 to start the list:

MT Manager
APKLab

What exactly are these tools? Apk editors?
How do i download the apklab app from github as i can only see the source code

You have to install VS Code first, then you can go to extensions and add APKLab as an extension.

Oh… so its for a pc, right?
Btw egate is written with vs code?

Yes, and no. eGate is written with Android Studio