### Website or app

reactjs.org

### Repro steps

1. Install React DevTools v4.20.0 in Firefox
2. Load reactjs.org in Firefox
3. Open Firefox DevTools
4. Observe error in console

![image](https://user-images.githubusercontent.com/1271509/137547605-e6ad3045-c20a-4828-9895-af46b8bb4db1.png)


### How often does this bug happen?

Every time

switch (EXTENSION_INSTALLATION_TYPE) {
    case 'public': {
      
      
      
      checkForInstalledExtensions([
        INTERNAL_EXTENSION_ID,
        LOCAL_EXTENSION_ID,
      ]).then(areExtensionsInstalled => {
        if (areExtensionsInstalled.some(isInstalled => isInstalled)) {
          callback(true);
        } else {
          callback(false);
        }
      });
      break;