July 2025 performance highlights for mozilla/gecko-dev focused on WebRender backdrop filters. Delivered edgeMode plumbing for blur/backdrop filters with Mirror edge mode, added relevant plumbing and changes to support the new edgeMode parameter. Implemented a targeted optimization to skip processing of backdrop roots when there is no child backdrop-filter, reducing wasted work in the display list builder. Improved blur rendering fidelity and visibility calculations by clearing expanded areas used for downscaling accuracy and accounting for blur inflation in visibility culling. Overall, these changes enhanced rendering performance, reduced unnecessary work, and improved visual fidelity of backdrop-filter effects.

June 2025 performance summary: Across mozilla/gecko-dev and servo/stylo, delivered foundational backdrop-filter support and root management to stabilize rendering of backdrop-filter primitives, enabling more robust visuals across engines and upcoming performance gains. Implemented backdrop-filter root isolation, updated shaders for normalized UVs, and extended WillChangeBits to reflect backdrop-root-related properties. Fixed clipping-related SwGL span shader issues, ensured cross-engine visual consistency for scrollbars in non-supporting browsers, and stabilized tests through targeted opacity and root establishment fixes for opacity and view-transition-name scenarios. Demonstrated strong collaboration between Gecko and Stylo teams, with improvements to the rendering pipeline, test coverage, and cross-engine consistency.