BCD Watch

BCD Changes Report

Summary of BCD changes from through 🔗

Browser Support Changes: +3, -0

Support increases (3)

API

  1. api ➞ RTCPeerConnection ➞ RTCPeerConnection ➞ configuration_alwaysNegotiateDataChannels_parameter Spec link
    Added to Firefox  ➞  2 of 3 engines
  2. api ➞ PerformanceContainerTiming ➞ toJSON
    Added to Firefox  ➞  2 of 3 engines

JAVASCRIPT

  1. javascript ➞ builtins ➞ Iterator ➞ includes
    Added to Chrome  ➞  3 of 3 engines

BCD Metadata Changes: 54

Show all 54 changes

Note: The following represent changes to BCD metadata keys in the reported time period. Keys are not implementations, and they don't represent commitments toward implementation, etc. A new key occurring is perhaps a signal that some implementer was serious enough to add the key. Many of the features that are 'removed' are usually just 'moved' or 'renamed', but we don't have great ways to highlight that.

Backfilled entries (32)

The entries in this section saw support information change since the report on Monday, 7 September 2026, but all the supported browser versions given were more than a couple of months old. Typically, these are cases of support information being updated long after the support actually landed in a browser, but nobody ever updated the BCD entry.

API

  1. api ➞ GPUSupportedFeatures ➞ feature_dual-source-blending Spec link
    Backfilled for Firefox  ➞  1 of 3 engines
  2. api ➞ SubtleCrypto ➞ decapsulateBits Spec link
    Backfilled for Firefox  ➞  1 of 3 engines
  3. api ➞ SubtleCrypto ➞ decapsulateKey Spec link
    Backfilled for Firefox  ➞  1 of 3 engines
  4. api ➞ SubtleCrypto ➞ encapsulateBits Spec link
    Backfilled for Firefox  ➞  1 of 3 engines
  5. api ➞ SubtleCrypto ➞ encapsulateKey Spec link
    Backfilled for Firefox  ➞  1 of 3 engines
  6. api ➞ TrustedHTMLParserOptions ➞ runScripts
    Backfilled for Chrome  ➞  1 of 3 engines
  7. api ➞ TrustedHTMLParserOptions ➞ sanitizer
    Backfilled for Chrome  ➞  1 of 3 engines

CSS

  1. css ➞ at-rules ➞ supports ➞ at-rule Spec link
    Backfilled for Firefox  ➞  3 of 3 engines
  2. css ➞ properties ➞ list-style ➞ symbols
    Backfilled for Chrome  ➞  2 of 3 engines
  3. css ➞ properties ➞ list-style-type ➞ symbols
    Backfilled for Chrome  ➞  2 of 3 engines
  4. css ➞ properties ➞ margin-trim
    Backfilled for Chrome  ➞  2 of 3 engines
  5. css ➞ properties ➞ margin-trim ➞ block Spec link
    Backfilled for Chrome  ➞  2 of 3 engines
  6. css ➞ properties ➞ margin-trim ➞ block-end Spec link
    Backfilled for Chrome  ➞  2 of 3 engines
  7. css ➞ properties ➞ margin-trim ➞ block-start Spec link
    Backfilled for Chrome  ➞  2 of 3 engines
  8. css ➞ properties ➞ margin-trim ➞ none Spec link
    Backfilled for Chrome  ➞  2 of 3 engines
  9. css ➞ properties ➞ overscroll-behavior ➞ chain Spec link
    Backfilled for Firefox  ➞  2 of 3 engines
  10. css ➞ properties ➞ overscroll-behavior-block ➞ chain Spec link
    Backfilled for Firefox  ➞  2 of 3 engines
  11. css ➞ properties ➞ overscroll-behavior-inline ➞ chain Spec link
    Backfilled for Firefox  ➞  2 of 3 engines
  12. css ➞ properties ➞ overscroll-behavior-x ➞ chain Spec link
    Backfilled for Firefox  ➞  2 of 3 engines
  13. css ➞ properties ➞ overscroll-behavior-y ➞ chain Spec link
    Backfilled for Firefox  ➞  2 of 3 engines
  14. css ➞ properties ➞ line-clamp ➞ height-based_clamping
    Backfilled for Chrome  ➞  1 of 3 engines
  15. css ➞ properties ➞ text-decoration-skip-spaces Spec link
    Backfilled for Chrome  ➞  1 of 3 engines
  16. css ➞ properties ➞ text-decoration-skip-spaces ➞ all Spec link
    Backfilled for Chrome  ➞  1 of 3 engines
  17. css ➞ properties ➞ text-decoration-skip-spaces ➞ end Spec link
    Backfilled for Chrome  ➞  1 of 3 engines
  18. css ➞ properties ➞ text-decoration-skip-spaces ➞ none Spec link
    Backfilled for Chrome  ➞  1 of 3 engines
  19. css ➞ properties ➞ text-decoration-skip-spaces ➞ start Spec link
    Backfilled for Chrome  ➞  1 of 3 engines
  20. css ➞ properties ➞ zoom ➞ is_animatable Spec link
    Backfilled for Firefox  ➞  2 of 3 engines

WEBDRIVER

  1. webdriver ➞ bidi ➞ browsingContext ➞ load_event ➞ context_parameter Spec link
    Backfilled for Firefox  ➞  2 of 3 engines
  2. webdriver ➞ bidi ➞ browsingContext ➞ load_event ➞ url_parameter Spec link
    Backfilled for Firefox  ➞  2 of 3 engines

MATHML

  1. mathml ➞ elements ➞ a ➞ hreflang Spec link
    Backfilled for Firefox  ➞  1 of 3 engines
  2. mathml ➞ elements ➞ a ➞ target Spec link
    Backfilled for Firefox  ➞  1 of 3 engines
  3. mathml ➞ elements ➞ a ➞ type Spec link
    Backfilled for Firefox  ➞  1 of 3 engines

New entries (18)

The entries in this section were not found in BCD on Monday, 7 September 2026, but are now present. These usually do not have any support information attached to them, and often have no corresponding MDN page. Sometimes, entries that appear here also appear in the next section (“Removed BCD entries”) because of a Working Group deciding on a rename.

API

  1. api ➞ PerformanceContainerTiming ➞ toJSON
  2. api ➞ SubtleCrypto ➞ decapsulateBits
  3. api ➞ SubtleCrypto ➞ decapsulateKey
  4. api ➞ SubtleCrypto ➞ encapsulateBits
  5. api ➞ SubtleCrypto ➞ encapsulateKey
  6. api ➞ TrustedHTMLParserOptions
  7. api ➞ TrustedHTMLParserOptions ➞ runScripts
  8. api ➞ TrustedHTMLParserOptions ➞ sanitizer

CSS

  1. css ➞ properties ➞ line-clamp ➞ height-based_clamping
  2. css ➞ properties ➞ text-decoration-skip-spaces
  3. css ➞ properties ➞ text-decoration-skip-spaces ➞ all
  4. css ➞ properties ➞ text-decoration-skip-spaces ➞ end
  5. css ➞ properties ➞ text-decoration-skip-spaces ➞ none
  6. css ➞ properties ➞ text-decoration-skip-spaces ➞ start
  7. css ➞ properties ➞ zoom ➞ is_animatable

MATHML

  1. mathml ➞ elements ➞ a ➞ hreflang
  2. mathml ➞ elements ➞ a ➞ target
  3. mathml ➞ elements ➞ a ➞ type

Removed entries (4)

The entries in this section were found in BCD on Monday, 7 September 2026, but are no longer present. The reasons for this removal can be anything from an experimental proposal that was never supported to a property or value being renamed to something else.

API

  1. api ➞ HTMLMediaElement ➞ seekToNextFrame
  2. api ➞ TrustedParserOptions
  3. api ➞ TrustedParserOptions ➞ runScripts
  4. api ➞ TrustedParserOptions ➞ sanitizer