We don't have Chrome in Fedora so this leaves Firefox.
As long as there's no reliable data about how many users are affected
by this issue IMHO the whole discussion is bulls**t.
Firefox and it's new policies are open to interpretation. It's debatable whether add-on signing actually constitutes DRM or is something more like what Fedora does with it's *.rpm packages and 'dnf' validating official GPG keys from a single verified source. It's a thing that's meant to establish trust. Most add-on packages used by Firefox users in Linux are the same as those used by Windows/Mac users from the official Firefox extensions web-site.
Most users won't notice the change and will probably benefit from the added security. The web-browser has become the number one attack vector on the desktop for Linux/Mac/Windows. This merely prevents a malicious add-on from installing itself in the background or tricking the user into installing it through a software bundle or clicking something a website.
This FESCo ticket should have really been about making Chromium available from the official Fedora repositories. Google Chrome is the leading browser currently  and growing. It's also default on the two leading Linux distributions Chrome OS and Android. In a sense this forces users to use the official Google Chrome packages and these ship with proprietary DRM extensions and Flash which doesn't make sense.
Instead you should revise the ticket or file a new one and make this about packaging Chromium so that Fedora users who make Chrome their default can avoid having to use these proprietary schemes.