Brown sweet rice is a type of short grain sweet rice, and has more starch and is much stickier than usual short grain rice. This is why it’s also called “brown glutinous rice”, because it’s like glue, not because it has gluten.
It tastes chewy and earthy when cooked, and is great for mixing with other grains to make traditional Korean multigrain rice.
You can find it in the grain aisles of Korean grocery stores.