Thanks for commenting! The @clearFloats@ thing is definitely a mistake; we’ll fix it.
As for @@import@, I just tested a import statement without @url@-less in plain CSS (in Safari 5.1) and you’re right: @url@ is no longer required. Good to know, though I’m interested to know what browsers support this form of the import syntax. One advantage to the classic @@import url@ is that I know it’ll work everywhere.
Sass always prefers to use @url@ for external CSS files. The main difference between @url@ and no-@url@ in Sass is that the preprocessor will check the ones with no @url@ to see if they might be Sass partials, whereas @urls@ are always assumed to be external. (They’re also always assumed to be correct syntax—you don’t need quotation marks inside your urls in CSS, so Sass doesn’t include them, but if you include them yourself Sass doesn’t take them out.)