.m4a is a standard MPEG-4 audio file, commonly used by Apple Music and iTunes .
The "yummy" in the song is widely understood as a reference to sexual chemistry and intimacy within his marriage. 01 Yummy.m4a
The "01" indicates it is the first track of the Changes album. 01 Yummy.m4a
A "chill" mid-tempo track featuring a crisp bass line and plinking keyboards. 01 Yummy.m4a