Richard Hallows

That's correct. It'd be breaking change. We should only start to work on it near the time we're planning to release `17.0.0` so that we don't have a long-lived branch.

We chose to enforce a leading zero in `stylelint-config-standard` because we believed it makes the code more quickly legible. We favour legibility over minimising key strokes.

> We initially thought so too but were enlightened by @jeddy3 from Stylelint. I'm afraid I might have been wrong. The default PostCSS parser supports the interpolation and nesting I...

> Hmm okay @jeddy3. But if I recall correctly you said that setting the 'syntax' option in config simply didn't exist and it was only a CLI option That's correct....

SGTM. > Create a script that can run tests for rule and after run updates column and line. We can start with this and then go from there.

This is a great initiative. It reminds me of [this series of articles that look into improving JavaScript tool performance](https://marvinh.dev/blog/speeding-up-javascript-ecosystem/). I think it makes sense to limit this issue to:...

> not all rules will require a PR hence just reviewing can result in a checkmark That's correct. It was implied, but I should've made it explicit for clarity. >...

Nice to see your upstream changes in PostCSS making a dent in those timings!

SGTM. I've labelled the issue as ready to implement. Please consider [contributing](https://stylelint.io/contributing) if you have time.

@meerhimmel While waiting on the next release of csstree (the upstream package that powers this rule), you can amend the syntax in your config using the [`typeSyntax`](https://stylelint.io/user-guide/rules/declaration-property-value-no-unknown/#typessyntax--type-syntax-) secondary option: ```json...