If email contains attachment with non-ASCII name or filename (encoded as described in RFC2047), then these names do not display correctly in message view and in attachment index. Here's the example of incorrect display of filename encoded in KOI8-r (cyrillic)
[ Part 3, Image/JPEG (Name: "=?koi8-r?Q?=C4=D7=C9=D6=C5=CE=C9=C5_=CE=C5=C2=C5=D3=CE=D9=C8_=D4=C5=CC.jpg?=") 58 KB. ]
[ Not Shown. Use the "V" command to view or save this part. ]
Which really should display as
[ Part 3, Image/JPEG (Name: "движение небесных тел.jpg") 58 KB. ]
[ Not Shown. Use the "V" command to view or save this part. ]
--Max
Just as a note: Save command performs correct decoding of the filename before saving it to the file system.
Added proposed fix in Patches section of Tracker.