This changes a bit depending on the library and what license/deal structure type you selected, but in general, this means that your song was accepted by one of our licensing partners.
For non-exclusive libraries, this means that your song was sent to the library and has been accepted. It will be added to their library as soon as they process it. You can still pitch the song to other non-exclusive libraries and sync opportunities, and you might get a few more libraries in the future who decide to take the song and add it.
For exclusive libraries, your song was accepted and wil be added as soon as they process it. As a note, we don't place your songs in exclusive libraries UNLESS you selected an exclusive deal structure. If you receive a notification that your song has been licensed exclusively, the licensing partner has licensed the EXCLUSIVE right to the track, meaning you cannot release the track yourself, and also cannot pitch it to other sync opportunities, regardless of if they're exclusive or non-exclusive.