how do I know that Avast really found some cookies tracking me?

Avast recently messaged me with an alert, that they found some cookies which are tracking me, monitoring my online activity, etc. My question is, how do I know that Avast is not making this stuff up, just to scare me into paying them money for upgraded service?? Ken

probably an ad for buying additional avast programs (avast clean up i think)

https://www.howtogeek.com/241006/how-to-block-third-party-cookies-in-every-web-browser/
https://www.howtogeek.com/298429/clearing-your-cookies-all-the-time-makes-the-web-more-annoying/
https://www.geek.com/chips/understanding-and-dealing-with-web-browser-tracking-cookies-1310507/