We implemented this in the Daily build of the desktop app last year, using a staging environment for Firefox Sync. But Firefox Sync is called Firefox Sync because it’s built for Firefox. Thunderbird profiles, in comparison, have a lot more data points. This meant we had to build something completely different. As we started to spin up Thunderbird Pro, we decided it made more sense to have a Thunderbird account that would manage everything, including Sync. Unfortunately, this meant a lot of delays. So Sync is still on our radar, and we hope to have it next year, barring further complications. Source: https://blog.thunderbird.net/2025/09/state-of-the-thunder-mo...
In other words, it was more work to adapt Firefox Sync than they thought at the beginning. It's still actively developed so finger crossed it's coming soon.
Exactly this. Plus, I rarely have over 20 tabs and even when I'm close to that number I mainly use the 10 first ones. Vertical tabs is a cool feature but both modes are useful depending your needs.
Mozilla Foundation is a non-profit but Mozilla Corporation which develop Firefox is a for-profit entity.
There are other subsidiaries under the foundation umbrella like Mozilla.ai and MZLA/Thunderbird. This isn't something uncommon for large entity and there are many advantages. For example, it gives more freedom in term of decision making and spending to projects that aren't targeting the exact same consumer segment. Think about Thunderbird. Under Mozilla Corporation, it was always in the shadow of Firefox. Now, it's striving as an independent project.
It's easier to do small releases often. You have less chances to break multiple parts of the application. You also don't end up in a cycle of "Wait! I'll add just one more thing" which is very common with projects tend to less often.
> If you can provide a citation for this claim I'd get a subscription today. I don't pay for their side projects because I don't want them to take it as a signal of demand for VPNs, but if it's truly 100% profit I'd be willing to risk it.
Fair enough. They publish their annual financial report but it isn't splitted per project so it's hard to know for a fact with the public information we have access to. However, it isn't unreasonable to think that at the very least a percentage of the smaller products revenues are reinjected elsewhere in the organization (e.g Firefox) since the goal seems to be to diversify their income sources.
> People keep saying this, but given that it's never been tried you have no proof. And even if it were, what harm is there in opening up one more option for those of us who want to be really clear about what we're paying for?
It's been tried over and over in the FOSS community. Few projects are able to get decent money with donations (e.g. Thunderbird). However, it's nowhere near the complexity of a web browser.
For example, Thunderbird made almost $7M (USD) in 2023 for an average of $20 per donation which is 350k users out of 20M monthly active users [1]. Firefox has 10 times that number of users so we could estimate that they'd make $70M/year. That's far from $500M/year they're doing right now.
Folks on HN are good to talk the talk but not really to walk the walk. Not only they could give to developers or company like Igalia but they could also get a Firefox Relay/VPN subscription. They don't even need to use it and their money is going to be 100% profit for MoCo. Also, if we are realistic, the total money in donation that Mozilla could get would probably represent a drop in the ocean compared to their annual budget and the amount of money you need to develop a (complete) browser. It's way more complicated than creating yet another chrome skin.
You can do the same with Firefox. Simply use Beta, Dev Edition or Nightly. The first two are very stable. You just need to flip `xpinstall.signatures.required` to `false` in about:config.
In other words, it was more work to adapt Firefox Sync than they thought at the beginning. It's still actively developed so finger crossed it's coming soon.