Is it an error or feature in the stylelint rule "unit-no-unknown"?

Question

Stylelint shows an error for the key in the Sass map, because Linter suspects that the number should have some units. https://stylelint.io/user-guide/rules/unit-no-unknown/

$resolutions: (
  2x: 2dppx,
  3x: 3dppx
);

Answer 1

I would say this isn't the expected behaviour. Please file a report in the stylelint issue tracker.