MusicaFicta plugin for MuseScore
This plugin will make accidentals in the selection appear as editorial to indicate musica ficta. It does this through three transformations: resize accidentals smaller (based on magnification percentage in Sizes page of the Style dialog), center them horizontally, and place them above the staff either equivalent to two ledger lines above or two staff spaces above the note if it is above the staff already.
If a single note is selected and has an accidental, the plugin will process that accidental. In addition, the user can select a range to process all accidentals in that range or select individual accidentals to process.