How can I know if a karaoke song contains explicit content?

When browsing the catalog on KaraFun, the "Explicit Lyrics" item in the description indicates that the song may be inappropriate for young people.

If there's no indication regarding the nature of the lyrics, it means the song can be listened to by any public.
In order to limit the exposure of younger people to inappropriate lyrics, KaraFun offers a parental control.