M0+ Breakout Board
This breakout board combines both the Adafruit M0 Feather and the Sparkfun board. From the Adafruit board comes Lipo charging, and from the Sparkfun board comes the full breakout. The header pins for SWO programming are broken out, and a microUSB interface is provided just in case you do compile your own bootloader.
Both companies have provided tools to create their bootloaders. However do note that you'll have to use your own VID/PID for USB if you are planning to use it in your own products. The Adafruit bootloader is preferred since it is more up to date.
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