Let's talk about Firefox customization and userChrome.css

[Ponda]

Firefox is extremely customizable thanks to a particular file called userChrome.css. It allows to change the appearance of Firefox so that it can look exactly like Chrome, Safari or anything one can imagine (and then write into the file). Unfortunately, so far Mozilla lacked interest in exploiting this feature. There exist unaddressed idea  concerning this and proposing a strategy, but what I think we need is serious discussion between users and developers – what we want, why, how to do it right, whether it should be done at all and why. While users' arguments seem quite clear to me, I can only guess the reasons Mozilla never elaborated on this – resources and security.

But collectively, we aren't that dumb, and there are some community members who would love to spend hours of their free time figuring out how to implement while circumventing the issues – we just have to know what the issues are, exactly. If implemented properly, this could give Firefox enormous advantage over alternative browsers, especially considering all the "Styles" and hacks that already exists and just need official installation support. One of the most common discussions concerning design are floating tabs vs folder tabs and more compact design. With official support for userChrome.css we could have both, and more.

So, let's talk about it, discuss the issues, propose solutions. It's just chat, it can't hurt, but it can prove very valuable.

[Ponda]

When it comes to my personal opinion, I'm absolutely in, but I imagine it's hard due to security concerns. The solution would be to review these "Styles" manually, which would be very costly. But then Mozilla could introduce payments for developers to verify Styles and publish on addons.mozilla.org, with currently existing side-loading still available (and dangerous). Who knows, maybe even users fees to buy some of them? Arguably a dangerous step, but Mozilla needs money and as long as all "Styles" remain open source and side-loading is possible I cannot oppose. But even if it was to introduce just a few tightly controlled "Styles", it could still collaborate with trusted organizations or people (such as KDE or Gnome) to create and maintain them. Maintenance itself could be challenging, with ever-evolving browser underneath, and close integration between different Firefox components could prove difficult to overcome. But then, I'm just guessing cause afaik you never shared anything on this topic. Maybe now, with renewed Focus on Firefox and step up of communication quality with community?

[jscher2000]

I don't think Mozilla wants to reopen the portal to allowing global styling. Certainly it's reasonable to be concerned about causing bad user experiences. However, was it really that bad 10 years ago?

Before Firefox 57 and before the developer sold them, the Stylish extension and userstyles.org site provided a convenient way to distribute and apply modifications to the browser chrome. In a way, it was the wild west because review of submitted styles was limited and unofficial, but we all trusted users and style distributors to take responsibility for breakage.

This is not to say that there shouldn't be any controls on what CSS themes can do, but the usual pattern is that more we want to control, the longer it will take and less likely it will happen.