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Add Baseline regression notes #3187

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34f003a
Add Baseline regression notes
ddbeck Jul 28, 2025
89c742b
Merge branch 'main' into regression-notes
ddbeck Aug 11, 2025
fccb850
Structure the Baseline value change
ddbeck Aug 11, 2025
241e4e5
Add regression note for `createimagebitmap`
ddbeck Aug 11, 2025
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14 changes: 8 additions & 6 deletions features/content-visibility.yml
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Expand Up @@ -3,12 +3,14 @@ description: The `content-visibility` CSS property delays rendering an element,
spec: https://drafts.csswg.org/css-contain-2/#content-visibility
group: css
caniuse: css-content-visibility
# TODO: https://github.com/web-platform-dx/web-features/issues/1971
# Status changed: https://github.com/web-platform-dx/web-features/pull/2591
# 2025-01-30 — low → false — Safari hides text behind `content-visibility: auto` from "Find…" in the page.
# References:
# - https://github.com/mdn/browser-compat-data/pull/25781
# - https://bugs.webkit.org/show_bug.cgi?id=283846
notes:
- category: baseline-regression
date: 2025-01-30
message: >
The `content-visibility` feature regressed from newly available to limited availability.
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For any kind of extraordinary status change, it might also be useful to the tools consuming this info to encode it into the note:

old_status: low
new_status: false

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Good suggestion. I've made changes along these lines with fccb850. It also meant that I could drop boilerplate text from each message.

Upstream data reported that Safari prevented text in `content-visibility: auto` elements from being found with browser's "Find…" user interface.
citations:
- https://bugs.webkit.org/show_bug.cgi?id=283846
compat_features:
- api.ContentVisibilityAutoStateChangeEvent
- api.ContentVisibilityAutoStateChangeEvent.ContentVisibilityAutoStateChangeEvent
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15 changes: 9 additions & 6 deletions features/font-variant-position.yml
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Expand Up @@ -2,9 +2,12 @@ name: font-variant-position
description: The `font-variant-position` CSS property sets whether to use alternate glyphs for subscript and superscript text.
spec: https://drafts.csswg.org/css-fonts-4/#font-variant-position-prop
group: font-features
# TODO: https://github.com/web-platform-dx/web-features/issues/1971
# Status changed: https://github.com/web-platform-dx/web-features/pull/1958
# 2024-10-15 — low → false — Chrome, Edge, and Safari do not implement font synthesis for missing superscript or subscript glyphs.
# References:
# - https://issues.chromium.org/issues/352218916
# - https://bugs.webkit.org/show_bug.cgi?id=151471
notes:
- date: 2024-10-15
category: baseline-regression
message: >
The `font-variant-position` feature regressed from newly available to limited availability.
Upstream data reported that Chrome, Edge, and Safari did not implement font synthesis for missing superscript or subscript glyphs.
citations:
- https://issues.chromium.org/issues/352218916
- https://bugs.webkit.org/show_bug.cgi?id=151471
14 changes: 8 additions & 6 deletions features/link-rel-dns-prefetch.yml
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Expand Up @@ -2,11 +2,13 @@ name: '<link rel="dns-prefetch">'
description: The `rel="dns-prefetch"` attribute for the `<link>` HTML element is a hint to the browser that the page or user is likely to request resources from another domain, so the browser should preemptively resolve DNS for the `href` value's domain.
spec: https://html.spec.whatwg.org/multipage/links.html#link-type-dns-prefetch
caniuse: link-rel-dns-prefetch
notes:
- date: 2025-06-23
category: baseline-regression
message: >
The `<link rel="dns-prefetch">` feature regressed from newly available to limited availability.
Upstream data corrected an earlier report that Safari on iOS supported this feature when it did not.
citations:
- https://github.com/mdn/browser-compat-data/pull/27057
compat_features:
- html.elements.link.rel.dns-prefetch
# TODO: https://github.com/web-platform-dx/web-features/issues/1971
# Status changed: https://github.com/web-platform-dx/web-features/pull/3074/
# 2025-06-23 — low → false — On iOS, it was erroneously reported that this feature was supported.
# References:
# - https://developer.apple.com/documentation/safari-release-notes/safari-26-release-notes#Networking
# - https://github.com/mdn/browser-compat-data/pull/27057
15 changes: 9 additions & 6 deletions features/popover.yml
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Expand Up @@ -2,12 +2,15 @@ name: Popover
description: The `popover` HTML attribute creates an overlay to display content on top of other page content. Popovers can be shown declaratively using HTML, or using the `showPopover()` method.
spec: https://html.spec.whatwg.org/multipage/popover.html
group: html
# TODO: https://github.com/web-platform-dx/web-features/issues/1971
# Status changed: https://github.com/web-platform-dx/web-features/pull/1797
# 2024-09-18 — low → false — Safari on iOS has a bug that prevents dismissing popovers by touch.
# References:
# - https://github.com/mdn/browser-compat-data/issues/22927
# - https://bugs.webkit.org/show_bug.cgi?id=267688
notes:
- date: 2024-09-18
category: baseline-regression
message: >
The popover feature regressed from newly available to limited availability.
Upstream data reported that Safari on iOS had a bug that prevented light dismiss (tapping outside the element to close it).
citations:
- https://bugs.webkit.org/show_bug.cgi?id=267688
- https://github.com/mdn/browser-compat-data/issues/22927
status:
compute_from:
- api.HTMLElement.popover
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6 changes: 0 additions & 6 deletions features/streams.yml
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Expand Up @@ -2,12 +2,6 @@ name: Streams
description: The streams API creates, composes, and consumes continuously generated data.
spec: https://streams.spec.whatwg.org/
group: streams
# TODO: https://github.com/web-platform-dx/web-features/issues/1971
# Status changed: https://github.com/web-platform-dx/web-features/pull/2358, https://github.com/web-platform-dx/web-features/pull/2491
# 2024-12-19 — low → false — Regressed status to match Caniuse, which considers support beginning at BYOB shipping.
# 2025-01-30 — false → high — Split BYOB into a separate "readable-byte-streams" feature. Linked that one to Caniuse.
# References:
# - https://caniuse.com/streams
Comment on lines -5 to -10
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I fussed over this for a while and ended up deciding to omit the note entirely. The first note would say that the feature regressed, the second note would be some new category (advance? unregression?) showing that we more or less reverted the second note. It seemed to me that the correct course of action in that scenario would be to withdraw the note, so that's what I've done.

status:
compute_from:
- api.ReadableStream
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