2nd order offset. The offset from the <offset from the start of the file>

perhaps the delta between offsets

We’re gonna need the delta of deltas

MicrOberon

And so it falls to me to link the relevant SMBC: https://www.smbc-comics.com/comic/2011-02-17

I got into FreeCAD's python interface, and then Cadquery for 3d printing a few years back, and I think you've got about 70% of the solution.

Things you've got right:

   - Human-readable text file is source of truth
   - GUI editing is first-class, because it's easier to work on (most of the time)

Features your proposed solution is missing that I want:

   - Full power of an established programming language.  Yaml or json won't cut it.
   - Code and GUI on equal footing.  Edit in GUI -> see generated code.  Edit in code -> see result on model.

The main problem with Cadquery is that it's entirely code-first, and you lose out on the intuitiveness of GUI editing

One of the less obvious things I really like about dealing with code cad is that feature selection can be based on intent. Like "upper-rightmost feature" rather than "feature closest to this coordinate I just clicked". There's got to be a good way to incorporate this aspect into the "edit in GUI -> code is generated" step (without just requiring manual code editing), but I'm not good enough at UX immediately see it.