The M1 processor module contained an NXP i.MX6ULL SoC along with 4 MB SPI NOR memory, 512 or 1024 MB RAM and an 10/100 Ethernet PHY.
All that was put on an 35 x 35 mm sized LGA module which could be soldered to a much simpler to design carrier board. The module always stayed the same but the carrier board could easily be changed to customer requirements.
It was only sold to OEMs and discontinued in 2019.
Let us know if you want more or are looking into a custom made audio streaming solution.