Perhaps this question has been asked before, but I am unable to find it. The closest I got was someone asking about chicken skin after frying.
When a piece of meat with large nuggets or fat attached is braised or boiled, the fat can be seen on the surface of the braising liquid. When it has been cooked for long enough, no more oil/fat is being given off by the piece of meat, but the (often) whitish/yellow tissue remains. It has a really soft and melty texture but doesn't really seem fatty.
I personally really like this. But what is it actually? is it still fat? Is it healthy?