Function file_url 

pub(crate) fn file_url(path: &Path) -> String

A file’s address for Qt and the desktop: “file:///home/me/A%20b.pdf”, and “file:///C:/Users/me/A%20b.pdf” on Windows; what an address cannot hold as is (“#”, “?”, spaces, accents) percent-encoded, so the file itself is reached.