THERE IS A MISTAKE!
RSSI is relative size
DON'T LIE TO PEOPLE AND MISLEAD THEM
TECH COMPANY RESPONSIBILITY
PEOPLE SHOULD GET THE RIGHT FACTS AND KNOWLEDGE ABOUT PHYSICAL MATTERS
but this article is not about 802.11
Typically RSSI also in Cellular networks is relative. How Cellular modem gives out the value depends on the manufacturer and its interpretation. https://i.imgur.com/Tu17wZP.png
I've modified the description by adding a sentence that RSSI values represent a relative signal strength measurement whose actual meaning depends on the measuring device