For those who are seeing this, more context can be provided int he cf worker-types GitHub:
Using bindings
It’s recommended that you create an ambient type file for any bindings your Worker uses. Create a > file named
bindings.d.ts
in your src directory:
bindings.d.ts
export {}; declare global { const MY_ENV_VAR: string const MY_SECRET: string const myKVNamespace: KVNamespace }