• [Singleton Removals] Remove PlatformStrategies, replacing with per-page providers
• [Singleton Removals] Remove RuntimeEnabledFeatures and DeprecatedGlobalSettings, replacing them with use of per-page Settings.
• [Singleton Removals] Remove Theme (and related classes) singletons, replacing them with per-page Theme objects.

• [Moving] Move remaining settings in Settings.yaml WTF/WebPreferences*.yaml
• [Moving] Move WeCore/platform/ classes to PAL/ to enforce layering via the linker
• [Moving] Move legacy loading code to WebKitLegacy.

• [CSSValue <-> Style Split] Stop using CSSValue classes in Style code, creating new Style classes for remaining concepts and simplifying CSSValue classes to just be plain data
• [CSS] Add "context" for CSS classes so they can access a relevant ScriptExecutionContext for Settings/Caches/etc.

• [Testing] Split WebKit IPC code into a static library that we can test via unit tests.
• [Testing] Add preferences generation to WebKitLegacy/win (needed so we can stop updating testing defaults for it every time)
• [Testing] Move unit tests out of WebKitTools/TestWebKitAPI and into project specific directories (e.g. WTF tests go in Source/WTF/Tests, etc.)

• [Rationalize] Rationalize how settings should work with Service Workers. Probably requires a concept in WebKit that a Service Worker can only be shared by pages that have the same WebPreferences/WebDataStore/WKUserContentController/applicationNameForUserAgent etc.
• [Rationalize] Rationalize how WebPreferences and API::PageConfiguration specific settings interact.

• [Loading] Unify loading classes using the Fetch naming and behavior.
• [RunLoop] Unify runloop classes using the HTML EventLoop naming and behavior

• [Unify] Add support for viewports to all ports.

• [Naming] Replace usage of broad PLATFORM() macros with more targeted HAVE()/USE()/ENABLE()/OS() etc. Adding new predicates and predicate types when needed.

• [Unclear If Possible] Find a way to get rid of Widget tree in WebCore.