Was it always this easy? How could I have not known?
First, know the manufacturer of the part I want a CAD file of the package of.
Then find that manufacturer on this list:
https://www.digikey.com/en/resources/3d-models
From the manufacturer's link on that page, again find the part. If the part has a CAD model, it will be findable when narrowing searches from this level down.
The part will have a link to the cat files on the manufacturer's site, which may or may not be correctly indexed.
