I guess it also has to do with history. Before Metro 6 'internal' was the name of the port that Metro used as its own sample player. When the support for this, in Apple's sound manager, no longer existed in OS X, the 'internal port' was changed to refer to QTMI.
jonrandal, (or is it Randy?) If you do not let me abbreviate (such as DLS for the DLS plug-in) it will be very difficult and time consuming to communicate.
The answer to you question 'Where is it?' I do not know. Most components (and Apple calls AudioUnit plug ins 'components') are stored in the components folder within Drive:Library:Audio:plug-ins:components. I think Apple stores its components elsewhere. Info may be available from Apple somewhere but I do not know.