How does Jeppesen create its US charts? The Jeppesen and FAA IFR plates represent the same information in different ways. The FAA publishes its charts for free, but the underlying data that goes into the charts (e.g., exact coordinates of fixes, frequencies, etc) doesn't appear to be published in a structured format. The PDF files that the FAA publishes appear to be created using Bentley MicroStation, but do not seem to embed any useful metadata about what the various symbols mean.

Based on that preliminary research, I am wondering how Jeppesen creates their various charts, such as IFR approach plates? Do they simply take the FAA charts and manually create their own derived charts (which strikes me as tedious and error-prone)? Or is there some hidden repository of structured FAA data available somewhere that they use to create them?
FAA/NACO charts aren't masters, either

The master form of a FAA instrument approach procedure isn't the FAA/NACO approach plate for that procedure -- that plate is a derived document, just like the Jeppesen plate for that approach is.

The master, instead, is kept by the FAA in textual form as a set of Form 8260s. These provide a precise, formulaic description of any FAA approach procedure -- they're simply not in a form that's at all usable in the cockpit.

An example set of 8260s for the (rather special) KASE LOC/DME 15 approach can be found here.  Note that this contains exact records of fixes, governing obstacles, holds, and other procedure parts, as well as documentation about standards waivers and notes of changes.