The file is the score.
MusicXML is not an import filter bolted onto a proprietary format: it is the editor’s document. Everything on screen is a faithful view of a real MusicXML score, in every version ever published.
On opening an imperfect file, a review panel explains exactly what is wrong. Safe automatic repair removes what can be removed without guessing, and never invents music. Anything that needs a human decision is surfaced, not silently changed. A lenient mode lets vendor extensions pass as warnings, so files from other applications open smoothly.
Byte for byte, or not at all.
Open a score and save it without editing, and you get the identical file back: comments, processing instructions, attribute order, quoting style, whitespace and all. When you do edit, only the values you changed are touched. That fidelity is a design guarantee, verified by an extensive test suite, so Arpezia sits safely inside any workflow without quietly rewriting your documents.