This particular example is close to my heart: the definition files for things like JSON.parse() were written before the "unknown" type was introduced as an alternative to "any"

And because this "any" is coming from an external definition file, it can't be caught by tsc's --noImplicitAny nor eslint's no-explicit-any

Those two rules allow us to protect us from our own code, but not external definitions/libraries. Relevant GitHub issue here — https://github.com/microsoft/TypeScript/issues/26188