DownThemAll (2019)

You can use Firefox Developer Edition and make your own addon. It isn't exactly straightforward, especially the "communicate with external software" part (e.g. in Windows you need to put some entry in the registry to let Firefox know what program you need to communicate with) and communication has to be via JSON which in practice means you need to write some sort of proxy app.

But it is possible. I have made my own little addon that calls yt-dlp (previously youtube-dl) with the current URL to save videos from YouTube and other supported places (e.g. Reddit) with a single click. The addon communicates with a Python program to send it the current page's URL which in turn just changes to a predefined directory (where downloaded videos are stored) and calls yt-dlp with that URL.

I was a bit hesitant at first to bother with all that but eventually i decided that it is "my browser" so i should be able to do whatever i want with it and certainly adding a button to call a program with the current URL should be more than possible.

The downside is that Developer Edition updates way more often than regular Firefox which in theory might break stuff but personally i never had an issue with it.

No. Who would use it? The few hundred thousand who want Tree Style Tabs?

Separately, keeping a browser up-to-date with new standards and security fixes is a huge undertaking. You would need a lot of engineers invested in such a project.

By the way, Nils from DownThemAll is a great guy. He wrote a scathing blog post at the time Mozilla announced dropping support for "legacy" extensions. Wish I could find it.

Either of these may fit the bill:

PaleMoon

Waterfox Classic

Hi Stefano, Nils here, long time no see.

Yeah, it was 2006 when I joined you and Federico, if I remember correctly, while you and Federico started DownThemAll! in 2004. #201 is correct :D

2006 was really a long time ago...

DownThemAll! went through a lot of revisions since that time, including the work it took to make it restartless, then make it compatible with "electrolysis" and so on. And in the meantime ensure it didn't break with every Firefox release. But at the core the functionality kept the same. People contacting me with questions could be quite overwhelming - and I am sorry if some of you HN'ers mailed me and I didn't answer - but it was very enjoyable to see what different kinds of people were using our creation and get in touch with all kinds of folks that way, from students downloading lecture videos to movie editors downloading the "dailies", and everything in between.

I am still not happy mozilla decided they had to break all extensions, and I had to do a full rewrite as a WebExtension, and thus abandon a lot of features that simply are not possible anymore with that new API, while at the same time reinvent the wheel for the UI (now being forced to use vanilla HTML, which can be quite hard to get performant enough when people queue a couple of tens of thousands downloads at once). But the very core of functionality, namely selecting and queuing up a lot of links quickly, is still there, so I hope some people still find this new DownThemAll! WebExtension useful.

Lastly, while the last release was indeed 2 years ago, I keep meaning to fix some bugs and make a new release. I was already planning to set aside a lot of time this month for that, even before seeing DTA pop up on HN again. I guess this HN post can only motivate me more :D

Federico's death was incredibly sad. We only met once in person, but he was such a nice and humble guy, not just in real life but online too. I miss him too, may he rest in peace.

I (Nils) was the maintainer of it for many years at the point already, and I was genuinely considering to let it die for quite a while. I was furious at what mozilla did to the loyal and active extension community and especially on how they did it - essentially by decree without community interaction at all. I was part of the mozilla volunteer army, not just with DownThemAll! and a few other more minor extensions, but I also had been on the team reviewing add-on submissions - I think I reviewed something like 2000-2500 individual submissions including updates in the end - and contributed a few minor bits to Firefox itself. The carelessness of how mozilla approached this large chunk of their community, after declaring their "1 million mozillians" goal not too long before, was mindblowing to me.

I eventually decided not to let it die... DownThemAll! had been a big part of my life, and while I recognized that I had to dumb down the feature set, I saw a way to at least make the core stuff work, maybe. I am glad I tried it even though it required a considerable amount of time to fully rewrite this thing.

The net result of mozilla's move was that they killed a large number of useful extensions entirely, while the survivors then usually became available for Chrome as well thanks to the mostly shared API - DownThemAll! is available for Chrome as well right now - giving users even less incentive to stay with Firefox. Oh well.