css.properties.appearance - base-select data doesn't specify which types of select its supported on

[lukewarlow]

What type of issue is this?

Missing compatibility data

What information was incorrect, unhelpful, or incomplete?

Currently the data just has a single support entry for appearance:base-select, but this doesn't give a complete picture.

What browsers does this problem apply to, if applicable?

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

What did you expect to see?

I would expect an entry for "single dropdown select" aka <select>, but then also an entry for listbox select aka <select size="3"> or <select multiple>. And in future a separate listing for "multiple dropdown select" aka <select multiple size="1"> too (this doesn't support appearance: base-select yet)

Chrome shipped initial support for customisable select in version 135, but didn't support listbox selects until 145 (see https://chromestatus.com/feature/6222145025867776)

Safari Tech Preview recently shipped support for single select too but again it doesn't support listbox select yet. I believe these distinctions are important and warrant separate representations within the dataset (how best to do this I'm not sure)

Did you test this? If so, how?

N/A

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

No response

Do you have anything more you want to share?

No response

MDN URL

https://developer.mozilla.org/en-US/docs/Web/CSS/Reference/Properties/appearance

MDN metadata

MDN page report details

• Query: css.properties.appearance
• Report started: 2026-03-04T13:59:32.683Z