a facet or facetAnchor: "all" option?

In this Plot:

Plot.plot({
  marginLeft: 60,
  marks: [
    Plot.frame({ fill: "silver" }),
    Plot.barX(data, { x: "Cantidad", fx: "type", fy: "p28" })
  ]
})

we would like the silver frame to be present on all facets, including the empty ones (represented with an orange stroke). Should we add a facet: "all" or facetAnchor: "all" option?

(The orange stroke was added with Plot.frame({ stroke: "orange", facetAnchor: "empty" })).

The chart can be fixed currently by duplicating the mark:
[Plot.frame({ fill: "silver" }), Plot.frame({ fill: "silver",facetAnchor: "empty" })],

but it shows that something is missing.

Test & data: https://observablehq.com/d/faf63a6fe3950d75

(Feature request suggested by @rusosnith)

relevant links in the documentation:

• https://observablehq.com/plot/features/facets#mark-facet-options
• https://observablehq.com/plot/marks/axis

(there is a small error on the axis page, where it says "null - show on every facet" it should say "null - show on every non-empty facet")

Start with the facet mark options documentation and the linked Observable test and data to understand how empty facets and facetAnchor are currently handled. Compare the requested all-facet frame behavior with the existing duplicated-mark workaround, and update the relevant documentation example and tests so completion demonstrates the frame on both non-empty and empty facets.