Yes. ETag tracking has been a thing for decades: https://en.wikipedia.org/wiki/HTTP_ETag#Tracking_using_ETags https://en.wikipedia.org/wiki/HTTP_ETag#Tracking_

Yes. ETag tracking has been a thing for decades: https://en.wikipedia.org/wiki/HTTP_ETag#Tracking_using_ETags https://en.wikipedia.org/wiki/HTTP_ETag#Tracking_using_ETags