As part of the Downloads Panel redesign in bug 1269956, we plan to remove the remaining time from the toolbar, and only show the progress by filling the downloads arrow gradually. We can already move forward part of this design with a very simple code change whose result replaces the remaining time with the indication of whether a download has just completed, which is otherwise lost if a long download is running. I've made a patch and I've added the preference "browser.download.showProgressText" to re-enable the feature if we realize we're not ready for this change. However, the final plan is for the indicator to be completely different and simpler, so the preference will not be available anymore.
Created attachment 8775129 [details] Bug 1289774 - Show the attention state instead of the time remaining in the Downloads Indicator. Review commit: https://reviewboard.mozilla.org/r/67412/diff/#index_header See other reviews: https://reviewboard.mozilla.org/r/67412/
The team has evaluated the pros and cons of this intermediate state and the present conclusion is to implement the entire design in one go in bug 1270006.