In order to make bootloading easier across platforms the different firmwares are packaged together in a ZIP file that contains a manifest describing which files are used for what. Here's an example of a manifest, it should be called manifest.json:

{
  "version": 1,
  "files": {
      "cflie.bin": {
        "platform": "cf2",
        "target": "stm32",
        "type": "fw"
      },
      "nrf_cf2.bin": {
        "platform": "cf2",
        "target": "nrf51",
        "type": "fw"
      },
      "nrf_cload.bin": {
        "platform": "cf2",
        "target": "nrf51",
        "type": "bootloader"
      },
      "s110.bin": {
        "platform": "cf2",
        "target": "nrf51",
        "type": "softdevice"
      }
      "cf2_lua.bin": {
        "platform": "cf2",
        "target": "stm32",
        "type": "userapp",
        "origin": 524288
      }
   }
}

Each entry in the file describes one file, with the following attributes:

Currently only platform=cf2, target=stm32, target=nrf51 and type=fw is supported.