Manifest: badge purpose "monochrome" is only supported by Firefox

[marcoscaceres]

As the badge purpose "monochrome" is only supported by Firefox, it is at risk of being removed from the specification. Implementers should express interest in supporting this feature if they would like it to remain in the specification.

[mgiuca]

Chrome: Filed https://crbug.com/1096388

As I said on #833, I can't commit to us actually using this but I think it's useful to have it defined and I'll advocate for it to be used when an appropriate context arises.

[marcoscaceres]

Thanks @mgiuca, the feature is explicitly marked at risk in the spec, so we will await your feedback in #905.

[kenchris]

@aarongustafson I assume this would also be useful for Edge and the Microsoft design system - maybe something Microsoft would be interested in adding support for?

[fahei]

I find a blank version of the icon very useful. A one-color icon is already needed for the safari mask-icon to display the logo in the touch bar. User agents could do a lot with a blank, standard version of the normal icon e.g. when having a design schema to automatically fit the icon in the design schema: The icon color is red, background is black with a padding of x. It could also be useful for share-icon-generation, so the icon can easily fit to the share-icon-design.

[christianliebel]

Chrome: Filed https://crbug.com/1096388

As I said on #833, I can't commit to us actually using this but I think it's useful to have it defined and I'll advocate for it to be used when an appropriate context arises.

@mgiuca The crbug was marked as Fixed/Closed. Can that be interpreted as your support for this monochrome purpose?

[phoglenix]

I'm the last eng person on Chrome to touch icon purposes (not a PM!).
https://crbug.com/1096388 was tracking the rename of purpose "badge" to "monochrome". That part is done.
https://crbug.com/1114638 is tracking adding support for icons with purpose "monochrome" (not a commitment to do so).

I believe @mgiuca's comment is still accurate. Chrome is not actually using "monochrome" currently but would support it remaining in the spec because it's likely to be useful in the future.

[mgiuca]

Yeah so this is just in Firefox as far as we can tell.

I think @NotWoods renamed it in Firefox, correct? And it's landed in the spec. So that means it's renamed everywhere that it exists.

It isn't implemented outside of Firefox, so that puts it at risk in the spec, however, Google supports keeping it just because we think we'll want it some day. If it gets taken out of the spec due to only one implementation, c'est la vie. It can come back later.

[aarongustafson]

Just making a note here: Once this has broader adoption, we will need to add it to the Web Platform Tests. I am removing it from #666 so it doesn’t hold up CR.

[loyso]

Chrome M93 recognizes "monochrome" icon purpose for both primary icons and shortcut menus (jump lists).
https://bugs.chromium.org/p/chromium/issues/detail?id=1114638

It's not yet exposed in Chrome UI yet, will be used in Notifications in M94-M95.