Virtual package sf2-soundfont-gm is provided by:
dpkg-query: no packages found matching opl3-soundfont Desired=Unknown/Install/Remove/Purge/Hold | Status=Not/Inst/Conf-files/Unpacked/halF-conf/Half-inst/trig-aWait/Trig-pend ||/ Name Version Architecture +++-====================================-==========-==================================== ii fluid-soundfont-gm 3.1-5.3 all Fluid (R3) General MIDI SoundFont (GM) un musescore-general-soundfont-lossless <none> <none> (no description available) ii timgm6mb-soundfont 1.3-5 all TimGM6mb SoundFont from MuseScore 1.3 3 packages