I have read the USDT smart contract and there is no price re-adjustment. Only some management functions like blacklist addresses burn cash and of course the basic ERC20 functions.
But how do they re-adjust the price to be 'stable'
Is it done from outside?
Then do they have to do it for each exchange, using the exchange API?

More info is welcome!

First, a standard smart contract for an ERC-20 token, Digipound, was written anddeployed to a test Ethereum blockchain.  Next, three main functions were createdto implement each of the stages of the issue-trade-redeem cycle of a stablecoin.  Inthe issue stage, payments of GBP are accepted using the Stripe platform, triggeringa call to an API that is connected to the Ethereum blockchain, web3, to issue theaforementioned token. Digipound tokens can be traded through both the project orindependently.  In the redeem stage, a call to the web3 API writes a transaction toburn the Digipound tokens before calling the Stripe API to issue a payout of the ap-propriate amount of pounds back to the user. These functions were transformed intoa user experience via the Digipound website, which also kept track of the balance ofGBP in a reserve account connected to Stripe as well as a link to a block explorer,a blockchain search engine, to verify the amount of the Digipound tokens that wereissued.  These quantities were tracked in real time and displayed in a clear manneron the web application’s landing page, representing the auditing system