html.elements.optgroup - Incorrect `<optgroup>` support

What type of issue is this?

Incorrect support data (example: BrowserX says "86" but support was added in "40")

What information was incorrect, unhelpful, or incomplete?

Neither Chromium, Firefox, nor WebKit support <optgroup> fully and have not for many years and all versions.

What browsers does this problem apply to, if applicable?

Chromium (Chrome, Edge 79+, Opera, Samsung Internet), Firefox, Safari

What did you expect to see?

Partial support for all browsers.

Except maybe Firefox on desktop which can keep "full support". Though care should be taken to identify when Firefox started supporting <optgroup> since I am wary it did so on day 1.

Did you test this? If so, how?

Yes, using https://adrianroselli.com/demos/splitting-within-selects/index.html.

Chrome 120 / Windows 11:

• does not expose the <optgroup> within the accessibility tree.

Safari 17 / macOS 14.0:

• does not expose the <optgroup> within the accessibility tree;
• announces the <optgroup> as “dimmed” when using VoiceOver (likely a result of prior bullet);
• has insufficient contrast (1.4:1), making the text essentially useless to low vision users.

Firefox 118 / Android 13:

• announces the <optgroup> as “disabled” when using TalkBack (may be an issue in Firefox accessibility tree, but cannot inspect it);
• has insufficient text contrast (2.9:1).

Safari 17 / iPadOS 17.0.3:

• has insufficient text contrast.

Can you link to any release notes, bugs, pull requests, or MDN pages related to this?

Webkit:

• Bug 175817: OPTGROUP label is not readable on every OPTION, 22 August 2017

Chromium:

• Issue 755269: Optgroup accessibility, 14 August 2017.
• Issue 817579: HTML optgroup elements and their labels not represented in the accessibility tree, 28 February 2018.
• Issue 1130271: optgroup is incorrectly transmitted to the Accessbility API, 19 September 2020.
• Issue 1262384: <select> with <optgroup> should be announced to screenreader, 21 October 2021.

Do you have anything more you want to share?

No response

MDN URL

https://developer.mozilla.org/en-US/docs/Web/HTML/Element/optgroup

MDN metadata

MDN page report details

• Query: html.elements.optgroup
• Report started: 2023-12-18T17:28:34.010Z

Start with the MDN optgroup page and the linked WebKit and Chromium accessibility issues. Determine the appropriate partial-support ranges for Chromium, Firefox, and WebKit, including whether Firefox desktop should remain full support. Done means the browser-compatibility data reflects the documented behavior and historical support evidence.