Some Firefox users recently found an unwarranted add-on installed in their browsers. The add-on, which is a page tool tied to the popular online show "Mr. Robot," was installed for some users that are a part of Mozilla's Studies program. While not malicious, the add-on was installed without the users' knowledge and raised some alarm from fervent Mozilla fans.
https://www.notebookcheck.net/Mozilla-in-hot-water-after-installing-a-browser-add-on-for-some-users-without-their-permission.272622.0.html