/usr/ is in arduino-mighty-1284p 1-2.
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/usr/share/
/usr/share/doc/
/usr/share/doc/arduino-mighty-1284p/
/usr/share/doc/arduino-mighty-1284p/copyright
/usr/share/doc/arduino-mighty-1284p/changelog.Debian.gz
/usr/share/arduino/
/usr/share/arduino/hardware/
/usr/share/arduino/hardware/mighty-1284p/
/usr/share/arduino/hardware/mighty-1284p/boards.txt
/usr/share/arduino/hardware/mighty-1284p/bootloaders/
/usr/share/arduino/hardware/mighty-1284p/bootloaders/standard/
/usr/share/arduino/hardware/mighty-1284p/bootloaders/standard/ATmegaBOOT_1284P.hex
/usr/share/arduino/hardware/mighty-1284p/bootloaders/optiboot/
/usr/share/arduino/hardware/mighty-1284p/bootloaders/optiboot/optiboot_atmega1284p.hex
/usr/share/arduino/hardware/mighty-1284p/variants/
/usr/share/arduino/hardware/mighty-1284p/variants/standard/
/usr/share/arduino/hardware/mighty-1284p/variants/standard/pins_arduino.h