Quark is not, and never has been Philly. It is a low fat soft chese that comes originally from Norway. It has a slightly acidic taste and I use it mainly as a spread on crispbread with sliced cucumber and also in cooking as a low calorie replacement for cream/yoghurt (which I loathe)/creme fraiche
I much prefer the original Norwegian branded quark to the supermarket own brands, which are far too sloppy.
I used to get a brand called Golden Pastures (or something like that) at Waitrose, very spreadable. Then they produced their own brand sloppy product that doesn't spread well at all and discontinued the branded product. After a few months they reintroduced another branded product, Lindval,(or similar) but that hasn't been in stock for some weeks and there is no space for it so I assume it has been discontinued