>>8
But surely they (start and end tags) are redundant
Disregard that. Just read the format, I thought it meant "start and end of expression" (which is, of course, stupid) - not "start and end of line".
Of course, these also be made redundant through the match tag, which appears to match word boundaries (so why not line boundaries?)
Overall, this seems to be a solution to a problem that doesn't exist. Also XML is a very silly format to use for this.