The latest Firefox 3 (code name Gran Paradiso) development release (nightly) includes the very important and expected ability to pause downloads and resume them across sessions, that is even after restarting Firefox. The addition happened just before the code freeze that started this morning in preparation for the upcoming milestone 8 (M8) expected for mid September.
While the back end code is already in, the necessary user interface is still missing and should be available in the days to come. Since download resume depends not only on the browser but also on the server capabilities, some icon is needed to let the user know whether it is possible to pause the download or not.
With the new user interface for the Download Manager currently in the works I guess hiding the pause could be enough, but will ssee what the developers come up with.
On related news, an option to easily copy the download web address (URL) was also added recently.