Got some MOBI files that Calibre just can't convert - thought your plugin might be the trick.
MUst say its a bit weird on first use - I right click the file, plugin is there, only option was to Customise Plugin - only by clicking other files did I realise it only offered options when it found a suitable MOBI file.....
Maybe a note "Unable to unpack this file"??
So, I still have some files that are supposed to be MOBI and even your plugin won't touch - there is SOMETHING in them as opening in Notepad produces gibberish text.
Not a biggie now as I am not interested in reading these downloads - just curiosity piqued as to why they can't be tweaked (and they're not DRM'd)
(Even the eReader in Calibre won't deal with them!)