I would like to know how to reset a user set window size for an application to the one chosen by the developer. Are these settings usually stored in some plist file?
It depends on the Application, but mostly it's stored in the
defaults database. You can check for example Mail.app with:
defaults read com.apple.mail DefaultWindowState
If You do not know the
key just grep with "window" the output from
defaults read BUNDLE_ID
BUNDLE_ID is Your application bundle identifier which can be read like this:
APP_PATH="/Applications/Mail.app" defaults read "$APP_PATH/Contents/Info.plist" CFBundleIdentifier
You can try to change keys in plists using
defaults command or locate plist file in
~/Library/Preferences directory and change it manually.