Anyway, I found this:
100% Vegetarian Cheese made from microbial rennet
...which stands out against this, from WiKi:
Rennet is an enzyme mixture traditionally obtained from the stomach lining of young cattle, but now also laboratory produced. Vegetarian alternatives to rennet are available; most are produced by fermentation of the fungus Mucor miehei, but others have been extracted from various species of the Cynara thistle family.
Natural calf rennet is extracted from the inner mucosa of the fourth stomach chamber (the abomasum) of young calves. These stomachs are a by-product of veal production. If rennet is extracted from older calves (grass-fed or grain-fed) the rennet contains less or no chymosin but a high level of pepsin and can only be used for special types of milk and cheeses. As each ruminant produces a special kind of rennet to digest the milk of its own mother, there are milk-specific rennets available, such as kid-goat rennet especially for goat's milk and lamb-rennet for sheep-milk. Rennet or digestion enzymes from other animals, like swine-pepsin, are not used in cheese production.