The release adds the field-sizing CSS property for sizing form controls to their content, Notification actions in showNotification(), the unadjustedMovement option for requestPointerLock(), a pseudoElement option for getAnimations(), firstInterimResponseStart and finalResponseHeadersStart resource timing properties, the side property on SVGTextPathElement, and experimental text module imports with { type: "text" }.
developer.mozilla.org/en-US/docs/Mozilla/Firefox/Releases/152