Other improvements, such as error handling, testing, build & package, UI, etc.
Support for Web standards, such as HTML and CSS standard features on modern browsers, excluding CSS features that can be categorized in other projects
Layout enhancement, support for advanced layout spec, CSS Page Floats, CSS Grid Layout, CSS Multi-column Layout, etc.
Bugs on layout, not working as per the CSS spec, etc.
Issues on typography, support for CSS Text 3, CSS Text 4, CSS Fonts, etc.
Support for input document formats, such as EPUB, Web publications, etc., and embedding media types, such as MathML etc.
Issues on PDF output and printing
Support for CSS Paged Media and CSS Generated Content for Paged Media