Normally, Avast Free would insert its own certificate for HTTPS scanning into the browser. But it doesn’t in Firefox and Chrome browsers but does in Brave browser. Why is this?
Its certainly in my version 103 of Firefox.
That said I’m still using Avast Free version 22.5, you don’t say what version of Firefox and Avast you are using.
Oops, I forgot to mention I’m using latest version of Avast Free Beta 22.8.6028 (build 22.8.7470.734) and latest versions of Chrome and Firefox. I tried repairing and reinstalling but still no Avast Certificate in these browsers but there is in Brave browser.
Web Shield still works even though the Avast Certificate is not installed. I hope the Avast Team can inform us whether not having the Certificate installed in Chrome and Firefox is a bug or intentional.
BTW, restoring Settings do not restore the settings in Do Not Disturb Mode.
I just wonder how easy it would be to get back to the regular release of Avast and see if this is only an issue with the latest beta version.
I did miss that you posted in the Avast Beta sub-forum 
I remember when I used the regular release, the Certificate were there. So no need to uninstall and reinstall because Restoring Settings do not restore everything and we have to manually restore some settings which take time.
Best for the developers to either fix it or tell us that they intentionally removed the Avast Certificate from Chrome and Firefox.
I was just trying to confirm this issue was introduced with this beta build.
You can report a bug from the Avast UI:
About Avast, from the Avast tray icon, assuming it is still there in this beta release.
I believe latest Avast does not use its own certificate for Firefox/Chrome, except for fallback. This is since Avast 2016.
Interesting, however it still begs the question where does it check there untrusted/revoked certificates mentioned in your quote ?
It works without changing the certificates and the security parameters and certificates are verified by the browser itself, including checks for untrusted or revoked certificates.
Also, why would the certificates be present in the (extract) list, image extract I posted in Reply #1
Thank you, NON, for the clarification. It would be good if Webshield works without changing the certificates.
But why does DavidR have the Avast Certificate in his version 103 of Firefox? It could be that it is stored among other Certificates but it is not used for Chrome and Firefox. Which explains why Brave browser has the Avast Certificate.
If you mean who are to check these untrusted/revoked certificates, it’s browser. You can see Firefox/Chrome warns about bad certificate accessing here:
https://badssl.com/
If MITM method was used, browsers (sometimes WebShield itself) also warns invalid certificate as WebShield checks it is valid or not and transmit the results via how Avast signs it.
Also, why would the certificates be present in the (extract) list, image extract I posted in Reply #1Avast certificate is used(reserved) for MITM as fallback method when these "new" method does not work somehow. I got that before.
So, there should be the certificate on Firefox/Chrome store, if things not changed since above.