I'll try this.

The way I have to resume downloads in Firefox is

1. Move the .part file to a temp file

2. Start the download again; a new .part file gets created

3. Pause the download

4. Move the temp file to the .part file, overwriting it

5. Unpause the download; it resumes from where the old .part file stopped

This is only necessary if a "one-time" download link gets interrupted part-way through, eg. by a flaky connection. Attempting to resume a one-time link like normal gets (I assume) a 400 response and FF kills the .part file.

I like using the aria2[0] download utility - I don't think I've downloaded anything bigger than a dozen megabytes through a web browser for the last several years, and this method allows me more protocols, multiple connections, and of course continuing downloads. That said, it's nice someone found a solution to the problem - makes life easier for everyone who doesn't use an external download utility... How do you even go about finding the solutions to bugs like this?

[0]: https://aria2.github.io/

This is the kind of weird obscure bug that I'd hope LLMs could help with. Apparently a simple model linked to the internet and search engine is not enough to find it.

Reproducing the issue may be the best next action.

Another feature that has been left broken in Firefox for many years, is the modal search highlight function, the thing that would darken the rest of the page besides your results, so you could easily see where it is... I really liked that feature.

https://bugzilla.mozilla.org/show_bug.cgi?id=1872349