BigBandSymbol6 is a symbol font kindly supplied by Denis Mitchell. It contains assorted symbols with which you can enhance a big band score. (Enter them in Mozart as text entries, using the Windows Character Map accessory, to select the characters.)
From Mozart version 10, for each music symbols font, music font 'meta-data' must be supplied in mozart Font Description (.mzfont) files. (This does not apply to text and other files.)
The .mzfont files supplied here allow 3rd party fonts obtained for earlier versions of Mozart to be used with Mozart 10 onwards.