Non-Object Responses in JSON
Returning a non-object as a JSON response (in particular returning an array) used to be a security vulnerability.
Firefox
Copying to the Clipboard from the Console
The Firefox Dev Tools console defines a copy() function which will copy text to the clipboard.
For some reason, using navigator.clipboard.writeText("asdf"), which seems to be the normal way to do this fires a rejected promise. Probably something to do with …