Let's assume Uniswap's domain and front end interface is taken down. How can I as a user manually remove my tokens from a liquidity pool? What do I need and todo?
You can call the Uniswap's contracts directly. Specifically, you should call the
Router02 contract, which handles all the details.
Depending on your use case, you need to decide which function to call, since there are many variants. You can find the documentation at https://uniswap.org/docs/v2/smart-contracts/router02/