Where are the files installed when you execute a mpkg file?
An "mpkg" file is a meta-package file, a file that can contain files and packages to be installed.

They also contain a "bill of materials" that lists the files installed (but not the files installed by the packages it might contain - they have their own bill of materials).

Therefore you need to find the package ID of the mpkg file and any packages it might contain.

The easiest way to do this is to have a look in the receipts folder. This occasionally moves but in 10.9 it is in /private/var/db/receipts.

If we installed our mpkg file recently then it is best to use find like so:

find /private/var/db/receipts -ctime 2


which will list all the receipt files changed in the last two days. The files found will have names that look like "com.company.application.bom" or they also end in ".plist". The file name without the .bom or .plist is a package ID.

Now we know a package ID we can ask pkgutil to list all the files installed and their location.

pkgutil --files com.company.application


This will produce a long list of all the files installed and where they are located.

You may see some who recommend methods using the folder /Library/Receipts but not all receipts are actually stored in there for some reason.