Popular Firefox add-on download manager DownThemAll, following not being updated to support Firefox version 57 Quantum, is now discontinued entirely.
The website going down, alongside the last update to DownThemAll's [GitHub repository](https://github.com/downthemall/downthemall) being over a year ago, shows that the open-source Firefox extension is no longer in development. In addition, the extension no longer works as of version 28 of the https://alternativeto.net/software/palemoon/ web browser that supports pre-Quantum Firefox extensions.
In light of this discontinuation, some of the most popular alternatives found on AlternativeTo include https://alternativeto.net/software/jdownloader/ and https://alternativeto.net/software/free-download-manager/. Though these are dedicated applications and not browser extensions, some newer and more obscure browser extensions, such as https://alternativeto.net/software/multithreaded-download-manager/, do exist.
As of this post, no one involved with the development of DownThemAll has commented on the website's expiration or the project's halted development.