Coinkite proposes BBQr (Better Bitcoin QR) — an open protocol for encoding files too large for a single QR code into a series of animated QR codes that can cross air gaps. Designed primarily for PSBTs and signed Bitcoin transactions, but also supporting CBOR, JSON, and plain text.
Air-gapped Bitcoin wallets had long struggled with QR-based transaction signing — large multisig PSBTs simply didn't fit in one QR code. BBQr solved this with a clean, efficient encoding scheme that was quickly adopted across the ecosystem by wallets like BlueWallet, Sparrow, and Nunchuk.
Disclosure: Coinkite Inc. is the maker of this product and the publisher of this site.
bbqr.org