According to Wikipedia:
“Agar or agar-agar is a gelatinous substance derived from a polysaccharide that accumulates in the cell walls of agarophyte red algae. Historically and in a modern context, it is chiefly used as an ingredient in desserts throughout Asia…Agar can be used as a vegetarian gelatin substitute, a thickener in jellies, ice cream and other desserts.”
I used agar quite a bit when I did my Ayurvedic training in the early 1990’s, now, not as much. I do use agar in the Pumpkin Custard recipe on my website and for the gluten free Pecan Pie recipe in The Gluten-Free Almond Flour Cookbook (purchase the book Amazon.com).