Unavailable. Nobody can download this version any more, with elm or with the Lamdera compiler: github.com/rakutentech/r10 exists but has no tag 2.1.1; Software Heritage not asked yet (this run's --swh-calls were used up); no fork with tag 2.1.1 found (60 same-name repos checked); no cached copy. Use another version.
These are colors that can be used for SVGs because SVGs don't accept Element.Attr as they are not part of the elm-ui package.
For all other colors, look into R10.Color.Attrs... modules.