Temporary staves in version 3
Question asked in https://musescore.org/en/3.0beta#comment-872352
What is a temporary/cutaway staff?
This is an easier way to create an ossia. Insert the notes in the measures you want to use as an ossia and check "Cutaway" in staff properties and only the measures with notes will be shown. You can put the notes in various measures and have multiple ossias if you need them.