Bluetooth car audio with track data
The feature uses Bluetooth AVRCP, the Audio Video Remote Control Profile. It's used for controlling the app from the receiver (e.g. play/pause buttons on a BT headset).

AVRCP level 1.3 is possible since ICS and improved in Jelly Bean; it allows all of 1.0 (play, pause, next,...) plus metadata information on the track itself (artist, track name, etc.). It was also backported into CyanogenMod7.2 (Gingerbread).

Players themselves have to support AVRCP 1.3 too, I guess.

Apollo might also support this. Or just search for AVRCP 1.3 in the store.