Mac app is still running after deleting Info.plist

Mac app is still running after deleting Info.plist

I want to build a Mac App from scratch. I manually created the required
folders of main app, Contents, MacOS, Resources, and dropped the binaries.
The only one I don't know how to create from scratch is "Info.plist". So,
I just copied one from the installed Applications on my machine, removed
all the unfamiliar keys, except the Executable and Package type (as APP).
Then I did a test. Before I copied and editted the Info.plist file, I
double-clicked the app icon in Finder. Not working, which is expected.
After I copied and editted the Info.plist file, it is working, which is
also expected. Next is what I don't understand. I removed the Info.plist
file, and double-clicked the app icon in Finder, it is STILL working!
My question is:
Did the first time running migrate the Info.plist information to some
secret place in the app bundle?
Is copying and editing an existing Info.plist file from other applications
a good practice for building an app from scratch?