• [varStore] Sort the input todo list with the same sorting key used for the opimizer's output (#3767).
• [otData] Fix DeviceTable's DeltaValue repeat value which caused a crash after importing from XML and then compiling a GPOS containing Device tables (#3758).
• [feaLib] Make FeatureLibError pickleable, so client can e.g. use feaLib to can compile features in parallel with multiprocessing (#3762).
• [varLib/gvar] Removed workaround for old, long-fixed macOS bug about composite glyphs with all zero deltas (#1381, #1788).
• [Docs] Updated ttLib documentation, beefed up TTFont and TTGlyphSet explanations (#3720).