A standard would let the XRP Ledger escrow issued tokens, not just XRP
Victoria Shinder1 min readXLS-85d, a token escrow standard proposed in the XRPL Standards repository, would extend the ledger's escrow objects beyond native XRP to issued assets. The proposal enables escrowing of IOU and MPT tokens, letting accounts lock issued tokens in escrow objects with support for freeze, authorisation and transfer rates.
It adds ledger fields including sfLockedAmount and sfIssuerNode to track locked balances for IOU and MPT escrows, and revises the transaction logic of EscrowCreate, EscrowFinish and EscrowCancel to handle trustlines, MPT authorisation, transfer rates and locked balances. Invariant checks are enforced on escrowed IOU and MPT amounts, and gateway_balances is extended so an issuer's outstanding and escrowed amounts can be read in one call rather than two.
What it means
Escrow on XRP was simple because XRP has no issuer. An issued token does: it can be frozen, it requires authorisation, it carries a transfer rate, and its balance lives in a trustline that the issuer can act on. Locking one therefore raises a question native XRP never posed - what an issuer may still do to an amount that is escrowed.
That is why the invariant checks and the gateway_balances change are the substantive parts rather than the escrow itself. A standard that lets tokens be locked without letting an issuer's total supply be computed in one call would create a reporting gap at every gateway, and the request to fix that came from the review thread rather than the author.