You mean the upper staff. Anyhow, I’m pretty sure Sibelius can export to MusicXml as well. Any better software is supposed to be able to do that.
MuseScore is a free open-source program that uses soundfonts to play and save. It isn’t so stable but the autosave is pretty good. It is also a bit rigid and the controls are through shortcuts that you have to dig up in the help PDF rather than the UI. I thought I recognized the fonts and layout.