The Chinese have a method for curing eggs in alkaline solution until they turn black and somewhat translucent, too.

With olives, there's basically no way to eat them off the tree and have them taste edible. They have to be processed in some way to remove the bitter compounds, usually by brining or curing. So using an alkaline brine is one method, and not that uncommon (even for other colors of olives).

Other uses of alkaline compounds in cooking include using a lye bath for browning for baking pretzels or bagels, certain types of springiness and chewiness for noodles (for example, for fresh ramen), and processing corn into cornmeal through nixtamalization.