01 09 18 15 Mp3: Charli Xcx Baby Girl

The track features electro-pop artist Uffie . Charli asked her to join the song after they bonded at a house party while helping an intoxicated guest into an Uber.

The numbers in your query likely refer to a specific associated with the song's leak history:

Metadata from a leaked rough demo indicates the song was recorded on September 3, 2015 (03/09/15).