Different owners of apps in /Applications depending on installation technique I have noticed that pre-installed as well as apps installed from the App Store located in /Applications show permissions like this:

drwxr-xr-x+  3 root     wheel  102 Jan  1  2014 Mail.app

whereas apps installed by drag-and-drop into the same folder look like this:

drwxr-xr-x@  3 johndoe  admin  102 Jan  1 15:55 Steam.app

Why do these apps depending on the installation technique get assigned different owners and groups? I am using a standard user account for installation (johndoe) if that's important. Also, why would it be a bad idea to change the owner of every app to root as is mentioned for example in Homebrew's FAQs:


  Did you chown root /Applications/TextMate.app? Probably not.


-- Homebrew FAQs
If an app is digitally signed, then the owner will be assigned to the System. As this is a requirement for apps distributed through the Mac App Store, then the apps that you see from there will likely be owned by the system and not you.

With apps that you download directly from a vendor, then they may or may not digitally sign their apps, in which case upon installation, you may or may not be the owner. Digital signing provides different privileges to how the app can interact with parts of the OS, like getting beyond the firewall without an annoying popup to the user every time, so you may see even developer downloaded apps signed.

Be careful of taking ownerships of signed apps, as this can corrupt the digital signature and you may be force to reinstall the app.