Foundation Passport Airgapped Bitcoin hardware wallet. Distinguishing feature: NO USB data port for signing. All comms via QR codes + microSD. Models - Passport Founder's Edition (2021): touchscreen, smaller form. - Passport Batch 2 (2022+): updated firmware. - Passport Core (2024+): improved hardware. Operation - Wallet generates PSBT on phone/computer. - User displays PSBT as animated QR on screen. - Passport reads QR via camera. - Passport displays signed PSBT as animated QR. - Wallet reads it back. For larger PSBTs: SD card transport. Backup - 24-word BIP39 seed. - Optional 25th-word pass…