Eiji Kitamura recently addressed in a talk at Google’s web.dev live the new COOP and COEP policies that dictate how browsers handle cross-origin resources. The new opener (COOP) and embedded (COEP) policies set up a cross-origin isolated environment that protects against Spectre attacks while restoring powerful, previously disabled features (SharedArrayMemoryBuffer and more).
The new policies thus enable developers to use shared memory across threads and high-resolution timers that were effectively disabled at the start of 2018 in light of Spectre.
