IIRC they're also aiming for most existing extensions to still work (and working with extension authors on this). The extensions will require updating, but the

IIRC they're also aiming for most existing extensions to still work (and working with extension authors on this). The extensions will require updating, but the base functionality won't be lost from the spin so an extension that used to work can be rewritten to still work. The Chrome API is just a base. There's a lot of misinformation about this switch floating around. The intention is to not break existing addons.