Mrrzy, it's malt vinegar, and it's glorious. It's milder than other forms of vinegar. I got into the habit of dumping it on fish and chips, along with too much salt, but the salt crystals were smaller, more powdery, than the usual ones over here. ("Salt Sense" is close.)

One thing that I think I discovered about the chip was they had a slightly sweet tast. I figure out how that happened when I cooked a potato that had been around a little while. Apparently, some of the starch had converted to sugar. I've found it's nearly impossible to do it on purpose, and I may be wrong about it all, but English chips were SO much better than what I get over here.