The Tracker SoM SMT application note is now available. This has highly technical information for production of boards using the Tracker SoM and other LCC modules.
https://docs.particle.io/datasheets/app-notes/an036-lcc-module-smt/
New Ethernet application note! This has detailed information on Ethernet on Gen 3 feather and B Series SoM devices. Also included is a library that implements Ethernet with cellular fallback when the connection between the Ethernet LAN and the Internet goes down.
https://docs.particle.io/datasheets/app-notes/an037-ethernet/