Intent to remove about:permissions

about:permissions was implemented in 2011 but never intentionally exposed to end users, i.e. we don't link to it from about:preferences#content or from the control center a.k.a. identity panel or anything. The reason for that is that we're not happy with the UI, and there's no clear path forward; in a sense it's already dead code. Two years ago, bug 933917 was filed on removing about:permissions. We should finally do this. The [hosts -> permissions] mapping used by about:permissions is fundamentally flawed. It doesn't work well with different permissions that may apply to either a full host or eTLD + 1, or permissions that differentiate between http and https. It's hard to communicate these nuances in this kind of UI where users are supposed to pick a "site" (whatever that means) first. There's a good chance users would get stuck at that first step. I do think we should have a place for advanced permission management besides the control center (where users need to visit a site so they can change its permissions). Host whitelists and blacklists for various permissions are currently scattered across about:preferences#content, about:preferences#security, about:preferences#advanced and probably other places I don't even remember. Obviously this is far from ideal. However, I think any attempt to centralize these UIs ought to keep their [permissions -> list of hosts] mapping. So about:permissions with its [hosts -> permissions] approach isn't even a good starting point for future work. You may wonder, since about:permissions is quite self-contained, why not just keep it around for the time being for those who few who accidentially discovered it? More than two years ago I introduced SitePermissions.jsm in bug 885366. It has proven useful as the backend for the control center and for Page Info > Permissions, making it trivial to add new permissions there. Unfortunately, it can't be used easily as a backend for about:permissions. This makes about:permissions and ongoing tax that a number of developers have paid over the years. As an example, these changes were needed to add Push notifications to the control center and Page Info: http://hg.mozilla.org/mozilla-central/diff/1dd7cc876cd1/browser/modules/SitePermissions.jsm http://hg.mozilla.org/mozilla-central/diff/1dd7cc876cd1/browser/locales/en-US/chrome/browser/sitePermissions.properties ... whereas these changes were needed to add them to about:permissions: http://hg.mozilla.org/mozilla-central/diff/1dd7cc876cd1/browser/components/preferences/aboutPermissions.js http://hg.mozilla.org/mozilla-central/diff/1dd7cc876cd1/browser/components/preferences/aboutPermissions.xul http://hg.mozilla.org/mozilla-central/diff/1dd7cc876cd1/browser/locales/en-US/chrome/browser/preferences/aboutPermissions.dtd http://hg.mozilla.org/mozilla-central/diff/1dd7cc876cd1/browser/themes/linux/preferences/aboutPermissions.css http://hg.mozilla.org/mozilla-central/diff/1dd7cc876cd1/browser/themes/osx/preferences/aboutPermissions.css http://hg.mozilla.org/mozilla-central/diff/1dd7cc876cd1/browser/themes/windows/preferences/aboutPermissions.css So from this perspective as well, we really should have gotten rid of about:permissions a long time ago. We've been wasting way too many resources on it. Thoughts? Have I missed something? Dao