The latter is more explicit, correctly handles some edge cases, and helps tag places in the code where we should look into replacing null with undefined.

#70020

Fixes #60807

part of strict null work

- Show feedback when action is completed
- Verbose reload action

- Exclude not supported extensions
- Show remote badge

Many `Promise.resolve(null)` should actually be `Promise.resolve(void 0)`. In other cases, we were missing a null return annotation.

ES6 promises like using undefined as their first argument instead of null. Both should behave the same behavior