a7d5ced created the issue

If the Open Connection wizard is launched, and if the More Options section is closed within the wizard, then blind users cannot access the More Options button by tabbing. They would need the assistance of a sighted person to click that button (I presume, since blind users might have their own workarounds when presented with GUI issues like this).
I note that the open-closed state of the More Options section is remembered by the app, but its default state during the first run is closed. I mention this on behalf of a blind friend seeking a WebDAV app. She can't use the feature built in to Windows 10 since the server she is connecting to (mine) uses a custom port number.