Unknown 2 Fill is a solid-style Icon from Outlined Fill - Material Symbols set.

The Unknown 2 Fill icon shows a circle divided diagonally, with a plus sign in the dark upper-left half and a minus sign in the light lower-right half. Drawn in the solid style on a 24px grid for clear, compact UI rendering. Use it for contrast controls, increase or decrease settings, comparison tools, and adjustment interfaces. It belongs to Outlined Fill - Material Symbols free set in the Google Material family.