Are there any “sugars” for Espresso which add brace/bracket highlighting to JavaScript editing? By “brace/bracket highlighting” I mean: when you select an opening or closing curly brace or a bracket while editing JavaScript in Espresso, the brace/bracket you’ve selected and its corresponding closing brace/bracket is highlighted with some visual cue (bold, background colour, anything). 

If not, would it be possible to develop such a sugar?
As far as I can see, there is not. Developing such a Sugar might not be possible from my (very limited) understanding of the Espresso plugin documentation – JavaScript text Actions look like the best match, but the API does not seem to offer the kind of access needed for automatic highlighting. Note I haven’t delved into the ObjectiveC plugin docs (because there are none – the headers included with Espresso are the docs, and my understanding of ObjectiveC and Cocoa is slim, to say the least).