Adds a field to PerfomanceResourceTiming to indicate the render blocking status of a resource. Currently from a developer perspective, the only way to determine which resources were actually render blocking is to rely on complex heurestics. The new field would instead provide a direct signal regarding the same.
Currently in order to determine which resources were actually render blocking and which ones were not, developers have to rely on heuristics. By providing a web exposed field, developers can get a direct signal from the browser regarding the render blocking nature of each resource.