Yes, I did mean the ldraw.xml file, found here:
But, as I said, when using that ldraw file I don't get some of the models that are listed in the file when I load it in LDD. For instance, there is part 64228 (AAA Battery Box) that is listed in the ldraw file but when I look at the parts list within LDD it is missing.
The reason for this that I have come up with is that the model files are not where LDD is looking for them or they don't exist. Likely the latter as I haven't downloaded any. I just want to be able to use some of the older pieces that are listed in the ldraw file but can't figure out what I am missing/not seeing/not doing.
This is why I wanted to ask the community where I should look for these, or to direct me to an appropriate place.