It's not a bug. It's an intentional choice by Mozilla that users should not be able to install software without the approval of Mozilla. They say it is for secu

It's not a bug. It's an intentional choice by Mozilla that users should not be able to install software without the approval of Mozilla. They say it is for security. But the signing portal is automated so this is only realistically for revokation after widespread damage has been done. The suggestion in the thread is to use the developer edition which is, in lineage, essentially aurora/alpha version (in the past naming scheme) and contains bugs and security holes. With modern Firefox if you want software freedoms you have to give up safety... or use the unbranded version which has no auto update and manually re-install the browser for every update.