With bug 812894 fixed, the getDownloadStatusNoRate helper function is only used for showing the total download rate in the Summary of the Downloads Panel, when there are some downloads running that are not visible in the panel itself. We have code to compute this rate, however it computes the slowest rate of all downloads rather than the sum of the download rates for hidden downloads, which would be more accurate. To simplify the code, we should likely compute the right rate, then get rid of getDownloadStatusNoRate and the associated localized string. Alternatively we should just not compute the rate if we don't want to display it.