…rently just supports braces.
Extract the functionality of expand-region.el into expand-region-core.el. The expansions depend upon that, and expand-region.el pulls it all together. While the dependency feature-wise is not circular (all the mode-specific expansions depend on the core, and not the other way around), expand-region.el should not load all of its expansions, making it impossible to cherry-pick what you want. Ref issue #24