Breaking this was kind of an explicit decision. See https://bugzilla.mozilla.org/show_bug.cgi?id=1222924#c6 (quoting the relevant bit of comment #5) and comment 7. I think if we care about FTP we can fix the icons for the file listing. But I'm pretty sure we're going to be removing support eventually, so I don't know how much of a priority fixing this will be.
Bug 1600490 Comment 3 Edit History
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Breaking app/filetype-specific icons was kind of an explicit decision. See https://bugzilla.mozilla.org/show_bug.cgi?id=1222924#c6 (quoting the relevant bit of comment #5) and comment 7. I think if we care about FTP we can fix the icons for the file listing. But I'm pretty sure we're going to be removing support eventually, so I don't know how much of a priority fixing this will be.