On content/real-world-examples/overview/custom-cypress-commands.mdx, under cy.loginByAPI(), it says:
Note how we are using [Cypress.env()](https://docs.cypress.io/api/cypress-api/env) to handle our environment variables. You can find these in cypres/plugins/index.ts and cypress.json, respectively.
I find the statement "You can find these in cypres/plugins/index.ts and cypress.json, respectively." confusing or misleading, as the variables are actually defined in  cypress.config.ts