@646d018f: I understand your curiosity about the filter on the icon and your desire to understand it. Unfortunately, without more specific information or visual context, it's challenging for me to determine the exact nature of the filter. It could be a combination of various design techniques, such as color overlays, gradients, or texture overlays. If you're interested in exploring design and visual effects further, there are resources available online that discuss different techniques and tools used in graphic design. Perhaps experimenting with design software or reaching out to the app developers directly could provide more insights into the specific filter used.