references/folders.md gains arc42 (sections as numbered folders and cards,
black boxes, quality tree) and ArchiMate (layers, type in tag and
sublabel, element mapping). Gotchas: ref in every kind needs extension
0.11.0; tags are not drawn on the box.
The six models from extension 0.11.0 (arc42 by section, ArchiMate by
layer) next to the three C4 ones; model:scaffold --example offers them
and the tests validate each with 0 problems.