- [kernFeatureWriter] Fix missing kerning in InDesign default paragraph composer when no explicit script/language is selected by registering all kerning lookups under DFLT/dflt (787).
- Use UPEM as the default caretSlopeRise regardless of italicAngle so that only the caretSlopeRun varies in VFs with slnt axis (804)
- [markFeatureWriter] Disable grouping of mark2base lookups by default, revert to building one lookup per mark class. The old behavior can be reenabled with groupMarkClases=True option (796, fixes 762 and 591).
- ufo2ft's feature writers now generates variable FEA for kern/mark/mkmk etc. and compile OpenType layout features only once per VF, instead of generating/compiling static features for each master and merge OTL tables with fontTools.varLib (provided that the masters do not have different features.fea). You can disable/force the old behavior by setting compileVariableFeatures=False (635).
- Added new `ftConfig` parameter to compile methods that allows to set various fonttools configuration options in the TTFont.cfg (see fontTools.config) (607).
- Avoid RecursionError when computing components' maximum depth and provide more info if/where cyclical references occur (813).
- Allow kerning between glyphs associated with different scripts by merging them into one lookup (808, 811).
- Apply DesignSpace `<variable-font>`'s "public.fontInfo" lib key to variable fonts (812, 816).
- [propagateAnchors] Do not propagate anchors to composite mark glyphs that already contain anchors (802, 815).