[@types/firefox-webext-browser] wrong type for browser.runtime.Port.postMessage argument

[wAuner]

DefinitelyTyped/types/firefox-webext-browser/index.d.ts

Line 4317 in 942c50b

postMessage: (message: object) => void;

According to the (not very detailed) MDN documentation for the postMessage function the parameter message needs to be serializable, but that doesn't mean it has to be an object. I'm currently developing a browser extension for Firefox and Chrome and was wondering why I did get a linter error when I passed in a string for Firefox, while that wasn't a problem for Chrome. At runtime it clearly works for both browsers.
The chrome types use any for this parameter, which probably should be the same for Firefox.