investigate fingerprinting and linkability risks of the Intersection Observer API
Support for the Intersection Observer API was added during the ESR60 development cycle. This API "provides a way to asynchronously observe changes in the intersection of a target element with an ancestor element or with a top-level document's viewport." and may add linkability or fingerprinting risks. See: https://bugzilla.mozilla.org/show_bug.cgi?id=1321865 https://developer.mozilla.org/en-US/docs/Web/API/Intersection_Observer_API