Figure out how to use the `key` property

[headquarter8302]

This value maintains the unique ID of an extension, or theme when it is loaded during development.
https://developer.chrome.com/docs/extensions/reference/manifest/key

The key property of MV3 is generated from the private key file exported by Chrome when packing an extension for the first time. Currently, every time I apply the property, Chrome won't load the unpacked extension. I'm probably implementing it incorrectly

[headquarter8302]

So, the proper way to do this is:

1. Pack the extension
   • This will generate the CRX and the private .pem key
2. Generate the public key pair from the .pem file using OpenSSL or ssh-keygen, encoded into Base64:

   openssl rsa -in <filename.pem> -pubout -outform DER | openssl base64 -A
   # or
   ssh-keygen -f <filename.pem> -y

3. Stuff it into manifest.json's key

That should be it, but chrome://extensions keeps freezing whenever I try to load the unpacked extension with the key

[headquarter8302]

And just like that, an SO answer comes to the rescue:
https://stackoverflow.com/a/52899058