I read about this a while ago when I was trying to see if I could build a device to see/hear through walls. It's possible just hidden behind a lot of beauracicy/acadamia bs.
Some consumer wifi company - linksys eero possibly? - some years ago was rolling out a home security feature which used signal differences in the mesh links to detect movement in the house. Not quite 1:1 with mapping, but similar.
There's been a bunch of "wifi as passive radar" in academic stuff for 10+ years, but w/out the modern image recognition stuff to boost it; most of if lacked public attention due to either academic paywalls or the difficulty of obtaining SDR gear in any affordable way at the time.
i use a variety of browsers and configs. I don’t recall which one burnt me (probably Tor Browser which has noScript built-in and thus runs 1st party js).