Not sure what it’s called. Maybe ghee. Doesn’t matter. Pop em out. Run them under room temperature water and use that knife to scrape it off. It will look purdy like the top. Cut a piece. Put on toast or whatever and enjoy!
I believe it is just sediment and husks from the trichomes, as stated above use a sharp knife to gently scrape or cut the bottom gunk off, don't believe you're losing anything but grit and a cannabinoid or two