I want to know the size of a linked page before I click it

In the last 10 years median desktop page size has quadrupled, and mobile page size has increased more than 8-fold; that trend does not appear to be changing. The internet is now ubiquitous and essential, but reliable access is not evenly distributed: lower income people are far more likely to be smartphone dependent, and access the internet on metered data plans that they occasionally or frequently exceed (see the Pew Research studies on the Digital Divide and Homework Gap).

Web page sizes directly impact all user access, but we are effectively flying blind when we surf the web. I want browsers to tell me exactly how large a page or file will be before I click a link so I can understand and make informed decisions, and I also want browsers to give me control to opt out of or selectively load large or data-intensive files or assets (like turn off autoplaying videos, or choose to see downsampled images, for example).