On OSX, having tried this patch, this QFileDialog::getOpenFileUrls() does succeed in presenting a native 'open file' dialog.

However, the 'filter' argument doesn't work as desired. It just displays the raw "*|Text File" string, which looks out of place, and doesn't cause any filtering.

http://doc.qt.io/qt-5/qfiledialog.html#getOpenFileNames

QT documentation appears to want a different syntax for filters. I tried the following just to verify understanding:

"Text Files (*);;C Files(*.c)"

It worked.

However, when it is reduced to:

"Text Files (*)"

Something it optimizing away the filter altogether, resulting in no filter functionality. (Which is probably fine).

Given this knowledge: It may make sense to not pass any filter at all, since it isn't actually filtering anything. It appears to simply be a placeholder for the Widget that is present on KDE dialog.