Everything sits at the top level, with no nested directories:
91m1_ppp-nrf54l15-v1.2.3/
├── README.md what each file here is for
├── merged.hex flash this on the host DK
├── zephyr.elf
├── zephyr.signed.bin
├── dfu_application.zip
├── .config
└── serial_modem_v{VERSION}_nrf9151dk_nrf91m1.zip firmware for the companion nRF9151 / SMA DK
93m1_ppp bundles carry no modem archive, their board having an integrated modem, and 93m1_at additionally has neither zephyr.signed.bin nor dfu_application.zip. File names are fixed so scripts and documentation stay valid after extraction.