URL with exclamation marks can't be opened in browser correctly.
E.g http://lederniergaulois.nouvelles-ecritures.francetv.fr/#!/episode1
opens the page http://lederniergaulois.nouvelles-ecritures.francetv.fr

Reason: NppNotification.cpp sets the wordchars without exclamation mark

    case SCN_HOTSPOTDOUBLECLICK:
    {
        notifyView->execute(SCI_SETWORDCHARS, 0, (LPARAM)"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789_-+.,:?&@=/%#()");

but if I understand RFC3986 correctly than this char is allowed

(page 12)
sub-delims = "!" / "$" / "&" / "'" / "(" / ")" / "*" / "+" / "," / ";" / "="