Marks
A mark is the cash value of one basket share. Each asset takes its mark from one of two sources. Pyth: the program reads a Pyth pull-oracle price update and enforces the RETF's own max age and confidence limits, with no keeper. Pyth quotes in USD, so use it with a USD-pegged quote token. Keeper rate provider: a small onchain account for assets without a Pyth feed, such as vault shares and LP tokens. Anyone can create one and become its keeper; creators choose which to trust. The program scales rates by 1e9 (1.0 = 1,000,000,000).
Paste a feed id from pyth.network. The app derives the sponsored feed account on this cluster and shows its price, age and confidence. On the Create page, pick Pyth feed as the mark and paste the same id.
A keeper pushes its rate. The program checks the rate's age and does not verify the number. The program reads Pyth marks from the Pyth receiver account.
The program refuses Token-2022 mints with a transfer-fee extension: the vault would receive less than the quoted deposit, which breaks pro-rata accounting. It also refuses transfer hooks, permanent delegates, non-transferable mints and frozen-by-default mints. It accepts all other Token-2022 mints and all classic SPL Token mints.