Bug 1600635 R[Core:CSS Parsing and Computation]Assertion failure: cachedStyles[i]->EqualForCachedAnonymousContentStyle(*cs) (cached anonymous content styles should be identical to those we would compute normally), at /builds/worker/workspace/build/src/layout/base/nsCSSFrameConstructor.cpp:3954
Bug 1658780 R[Core:CSS Parsing and Computation]Update the prefers-contrast media query to use the new more/less keywords
Bug 1655392 R[Core:DOM: Editor]Split `HTMLEditor::HandleDeleteNonCollapsedSelection()` to range computation part and modifying DOM tree part
Bug 1659274 R[Core:Graphics: WebRender]Silence build warnings in SWGL linear_composite
Bug 1656081 R[Core:Layout]Use ComputeSizeWithIntrinsicDimensions for iframe in nsSubDocumentFrame::ComputeSize()
Bug 1658198 R[Core:Layout: Columns]Huge performance degradation on Firefox 79 when opening web pages
Bug 1658524 R[Core:MFBT]ToResultInvoke should also work with RefPtr/nsCOMPtr
Bug 1658650 R[Core:Networking]Remove hasValidTransientUserAction from DocumentChannelCreationArgs
Bug 1568130 A[Firefox:Menus]Autohiding menu bar prevents web content from getting the keyup event for the Alt key
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Changes to 10 bugs - 9 fixed.