27477 [H] Tabs (cla: yes, f: material design, framework)

27481 Move Brightness to dart:ui in the engine (#27479). (cla: yes, framework)

27487 [H] Make NotchedShape more practical to use (cla: yes, f: material design, framework)

27501 Update docs for initstate(), didUpdateWidget(), dispose() (cla: yes, d: api docs, framework)

27502 Make a kReleaseMode constant that is public. (cla: yes, framework)

27504 Added support for the Galician language (material_es_GL.arb) (a: internationalization, cla: yes, framework)

27505 Remove icudtl.dat from APK asset size checks (cla: yes, team)