JimDanner

According to [MDN](https://developer.mozilla.org/en-US/docs/Mozilla/Add-ons/WebExtensions/API/runtime/getBackgroundPage), the `browser.runtime.getBackgroundPage` function returns a promise that may resolve to `null` when called from a private window. Perhaps it should be added to overrides.ts.

thunderbird-webext-browser: update of definitions to API version Thunderbird 127.0

4

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