Disable the use of the "com.apple.quarantine" extended attribute on Mojave
If I understood your question clearly, here is the solution that you can use to disable it completely. 


Open Terminal 
Type following command

sudo defaults write com.apple.LaunchServices LSQuarantine -bool NO

After that, reboot, and you should be set. 


If you want to disable quarantine for files already downloaded


Open Terminal.
Execute the following command:

xattr -l /path/to/application/applicationName.app

You will see output similar to: 




To remove an extended attribute manually, type the following command in Terminal 

   xattr -d com.apple.quarantine /path/to/application/applicationName.app