migration guide for flutter/flutter#186916

## Presubmit checklist

- [ ] If you are unwilling, or unable, to sign the CLA, even for a
_tiny_, one-word PR, please file an issue instead of a PR.
- [ ] If this PR is not meant to land until a future stable release,
mark it as draft with an explanation.
- [ ] This PR follows the [Google Developer Documentation Style
Guidelines](https://developers.google.com/style)—for example, it doesn't
use _i.e._ or _e.g._, and it avoids _I_ and _we_ (first-person
pronouns).
- [ ] This PR uses [semantic line
breaks](https://github.com/dart-lang/site-shared/blob/main/doc/writing-for-dart-and-flutter-websites.md#semantic-line-breaks)
  of 80 characters or fewer.

flutter/flutter@8bdce07...b7cb925

2026-06-12 engine-flutter-autoroll@skia.org Roll Skia from cadbde1ec4b7 to 8c89bf2b0ee3 (5 revisions) (flutter/flutter#187926)
2026-06-12 engine-flutter-autoroll@skia.org Roll Packages from 1b56cde to b78ad83 (5 revisions) (flutter/flutter#187928)
2026-06-12 engine-flutter-autoroll@skia.org Roll Dart SDK from f3441f2067ae to f6c31f4c3a63 (17 revisions) (flutter/flutter#187924)
2026-06-12 engine-flutter-autoroll@skia.org Roll Fuchsia Linux SDK from 2KosSR4ONUjIB7tP_... to A3eaUn9mQ_EkSNxVI... (flutter/flutter#187923)
2026-06-12 engine-flutter-autoroll@skia.org Roll Skia from a2228b926c68 to cadbde1ec4b7 (9 revisions) (flutter/flutter#187921)
2026-06-12 kustermann@google.com Remove dynamic module loading code in flutter web engine (flutter/flutter#187777)
2026-06-12 matt.kosarek@canonical.com Remove EnableTransparentWindowBackground because it did nothing important and because Windows 10 does not support DWMWA_SYSTEMBACKDROP_TYPE (flutter/flutter#187848)
2026-06-12 engine-flutter-autoroll@skia.org Roll Fuchsia Test Scripts from dQ4PjIJB5kZFU8Y32... to EmfiOMUge_nnNS33B... (flutter/flutter#187912)
2026-06-12 mvincentong@gmail.com Clarify RichText selection docs (flutter/flutter#186844)
2026-06-12 1063596+reidbaker@users.noreply.github.com Custom KGP task and migration to AGP api for geting kgp version (flutter/flutter#182788)
2026-06-12 engine-flutter-autoroll@skia.org Roll Skia from f61acb31edf8 to a2228b926c68 (5 revisions) (flutter/flutter#187896)
2026-06-12 bdero@google.com [Flutter GPU] Expose ASTC HDR texture formats (flutter/flutter#187715)
2026-06-12 awolff@google.com Expand coverage of android_hardware_smoke_test. Add image, text, blend mode, and blur tests. (flutter/flutter#187600)
2026-06-11 bdero@google.com [Flutter GPU] Add blit operations (flutter/flutter#187289)
2026-06-11 bkonyi@google.com [flutter_tools] Fix version cache git fallback performance regression (flutter/flutter#187400)
2026-06-11 nshahan@google.com Rewrite `-d web-server` hot reload/restart tests (flutter/flutter#187453)
2026-06-11 bdero@google.com [Impeller] Allow sampling textures with manually-uploaded mip levels (flutter/flutter#187729)
2026-06-11 154381524+flutteractionsbot@users.noreply.github.com Sync CHANGELOG.md from stable (flutter/flutter#187884)
2026-06-11 47866232+chunhtai@users.noreply.github.com iOS a11y sets header trait based on heading level (flutter/flutter#186916)
2026-06-11 engine-flutter-autoroll@skia.org Roll Skia from 9f02102df298 to f61acb31edf8 (19 revisions) (flutter/flutter#187869)
2026-06-11 engine-flutter-autoroll@skia.org Roll ICU from ee5f27adc28b to d578f2e8b7bd (8 revisions) (flutter/flutter#187829)

If this roll has caused a breakage, revert this CL and stop the roller
using the controls here:
https://autoroll.skia.org/r/flutter-packages
Please CC louisehsu@google.com,stuartmorgan@google.com on the revert to ensure that a human
is aware of the problem.

To file a bug in Packages: https://github.com/flutter/flutter/issues/new/choose

To report a problem with the AutoRoller itself, please file a bug:
https://issues.skia.org/issues/new?component=1389291&template=1850622

Documentation for the AutoRoller is here:
https://skia.googlesource.com/buildbot/+doc/main/autoroll/README.md

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After some testing UIAccessibilityTraitHeader actually means heading in
iOS, the voice over will announce "heading" if set.

The header in flutter has a different meaning, which is the banner (e.g.
app bar. or html \<header\>). This PR fixes the mistranslation.

I will prepare a breaking change doc for this.

## Pre-launch Checklist

- [ ] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
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- [ ] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [ ] I signed the [CLA].
- [ ] I listed at least one issue that this PR fixes in the description
above.
- [ ] I updated/added relevant documentation (doc comments with `///`).
- [ ] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [ ] I followed the [breaking change policy] and added [Data Driven
Fixes] where supported.
- [ ] All existing and new tests are passing.

If you need help, consider asking for advice on the #hackers-new channel
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If this change needs to override an active code freeze, provide a
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[Contributor Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#overview
[AI contribution guidelines]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#ai-contribution-guidelines
[Tree Hygiene]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md
[test-exempt]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#tests
[Flutter Style Guide]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md
[Features we expect every widget to implement]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Style-guide-for-Flutter-repo.md#features-we-expect-every-widget-to-implement
[CLA]: https://cla.developers.google.com/
[flutter/tests]: https://github.com/flutter/tests
[breaking change policy]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Tree-hygiene.md#handling-breaking-changes
[Discord]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Chat.md
[Data Driven Fixes]:
https://github.com/flutter/flutter/blob/main/docs/contributing/Data-driven-Fixes.md