Is there a better QuickLook plugin than the built-in for quicklooking applications?
Something that would show more of the info define in
Foobar./Contents/Info.plist, like version number and bundle identifier for example would be ideal.
Simple answer, no.
More complex answer is still no, but that doesn't mean it can't be done (Late Night Software's Script Debugger overrides the default QuickLook viewer for applications (com.apple.application) but you as the user don't see any difference).
The qlgenerator that does the job is StandardBundles.qlgenerator and is found in the /System/Library/QuickLook/ folder which is OSX's base folder for all QuickLook plugins that are OSX base types such as applications, Text files or Emails.
It provides the QuickLook functionality for the following base file "types".
Any replacement plugin would have to provide all the functionality of the existing plugin, in this case the Preference Pane quick look functionality.
Plugins live in 4 different places, and the order in which plugins are preferred is as follows:
Overriding the system default behaviour for .app can therefore be done with the following caveats:
So yes it can be done, but nothing currently exists in the public domain that provides this functionality and therefore something would have to be written bespoke to provide it.
If it was implemented, using it has it's issues since it would be for an OS X base type... so replacing the base type is not a good idea; the priority of the plugins is not fixed and you cannot be sure that the plugin would actually be the one to run.