Rechecked.
https://github.com/xbmc/xbmc/blob/master/xbmc/music/karaoke/karaokelyricstext.cpp#L497
https://github.com/xbmc/xbmc/blob/master/xbmc/music/karaoke/karaokelyricstext.cpp#L606
https://github.com/xbmc/xbmc/blob/master/xbmc/music/karaoke/karaokelyricstext.cpp#L686
For other cases seems to be OK with wstring.