relnote(116): CSSPropertyRule enabled in Fx nightly by default

[bsmth]

The pref layout.css.properties-and-values.enabled is set to true (enabled) on Nightly in 116. This allows for using the following APIs:

• CSSPropertyRule

• CSSPropertyRule.inherits

• CSSPropertyRule.initialvalue

• CSSPropertyRule.name

• CSSPropertyRule.syntax

• registerProperty()

And the following CSS syntax:

@property --item-size {
  syntax: "<percentage>";
  inherits: true;
  initial-value: 40%;
}

pen/demo:
https://codepen.io/bsmth/pen/xxQpVow?editors=0111

Related issues and pull requests:

• Parent issue [API] Pref layout.css-properties-values-api enabled on nightly content#27756
• Content (Exp Features): relnote(116): CSSPropertyRule and registerProperty() enabled in Fx nightly content#27902

Bugzilla:

• BUG-1840480

[chrisdavidmills]

LGTM; nice work @bsmth

[bsmth]

Thank you

[ZuBB]

I spent an hour this morning and found that this does not work(broken?) in the nightly https://bugzilla.mozilla.org/show_bug.cgi?id=1846488

Right now, information about the presence of this feature in v119 is incorrect and may confuse users. Does it make sense to revert it?

[bsmth]

I spent an hour this morning and found that this does not work(broken?)

I'm sorry you wasted time on this! I've amended the entries in the linked PR with a note linking to https://bugzilla.mozilla.org/show_bug.cgi?id=1846516 ("Support interpolating registered custom properties") which you can track for the fixes and improvements.