Augmented it with a bit of Ruby in order to find the "SUFeedURL", which if using the `http` protocol, means that an application is vulnerable.
% plutil -p /Applications/iTerm.app/Contents/Info.plist| grep SUFeedURL
"SUFeedURLForFinal" => "https://iterm2.com/appcasts/final.xml"
"SUFeedURLForTesting" => "https://iterm2.com/appcasts/testing3.xml"