They seem to at least do some basic unicode case folding. Don't know if it's full support, though.
In a search for the character 'á', all of the below captures it:
Code:
(á)
(\x{00E1})
(\p{Ll})
and \u\1 changes it to 'Á'
But I've no idea if it's limited to a certain subset of unicode (or if it handles all the ways á can be represented).