owner-nrf52sdk/nRF5_SDK_15.3.0/documentation/licenses.txt

See the top of each source file for the license under which the file is 
released.
The following licenses are used in the nRF5 SDK:
 
   i) nRF5 SDK license: The majority of the source code included in the 
      nRF5 SDK (nRF5_Nordic_license.txt)

  ii) nRF5 Garmin Canada license: Files released by Garmin Canada 
      included in the nRF5 SDK (nRF5_Garmin_Canada_license.txt)

 iii) SoftDevice license: The SoftDevice and its headers 
      (..\components\softdevice\sxxx\doc\<license file>)

  iv) ARM 3-clause BSD license: CMSIS and system files (..\components\toolchain)

   v) FreeRTOS license: FreeRTOS configuration files (FreeRTOSConfig.h 
      in the examples that show how to use FreeRTOS)

  vi) Third-party licenses: All third-party code contained in 
      ..\external (respective licenses included in each of the imported
      projects)