http://w3c-test.org/web-animations/interfaces/Animatable/animate.html
http://w3c-test.org/web-animations/interfaces/KeyframeEffectReadOnly/spacing.html

These failures need analysis, but may point to low-hanging fruit for improving interop. Judgement is required, the failures may be entangled with spec issues.

See  issue 651572  for the source of this data, which includes failing subtests.

Note: Results may have changed in the interim.