Comment by WillAdams

That's an excellent question.

Also, how are tool definitions to be handled? Each program seems to have their own approach, though some will place the tool description in comments. CutViewer is notable for doing this, and is the example I have been following in:

https://github.com/WillAdams/gcodepreview

(which is quite a different project)

EDIT: Note that the comment system which Cutviewer uses seems to be something of a de facto standard --- Carbide Create uses this same scheme.