Sadly this addon can't be trusted anymore. I know that the development of addons isn't really financially viable and that the addon will still work in the future. But selling out to a company like avast is really a punch in the face.

avast is such a trustworthy company that at one point firefox forbid their addons on this browser (german news article): https://www.heise.de/newsticker/meldung/Mozilla-blockiert-Firefox-Addons-von-Avast-und-AVG-4602939.html

Also:
"They show that the Avast antivirus program installed on a person's computer collects data, and that Jumpshot repackages it into various different products that are then sold to many of the largest companies in the world." (https://www.vice.com/en/article/qjdkq7/avast-antivirus-sells-user-browsing-data-investigation)