webanimations/accelerated-css-animation-with-easing.html r266241 added a test for a regression from r263506 regarding keyframes with explicit timing functions interfering with implicit timing functions of other keyframes. The red div (implicit timing function) must not be uncovered by the green div (with the explicit 'ease' timing function in a tiny keyframe interval). Running the test on MiniBrowser indeed the green div ends up using it the 'ease' timing function for the entire duration of its animation, leading to the red div to appear. Epiphany (WebKitGTK 2.28.4, without r263506) behaves correctly, like Chrome (84) and Firefox (80).