For most apps in Mac OS X, the only file created is the .app itself, since all the files the app needs are bundled with it. That makes installation/removal of apps a much simpler process with Mac OS X than with Windows. To install, drag the .app file to your Applications folder. To uninstall, drag the .app file to the Trash. It's that simple!
Some apps will create a .plist file that contains user preferences. These take up very little room and have no function if the app is removed. In most cases, you don't need to worry about files getting scattered all over your Mac during installation.
If the app doesn't have it's own uninstall package, you can use apps like
AppCleaner or
AppZapper to remove the app and all the files associated with it.
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