If you're seeing errors having the message "Non-Error exception (or promise rejection) captured with keys: x, y, z.", this happens when you a) call `Sentry.captureException()` with a plain object, b) throw a plain object, or c) reject a promise with a plain object.
You can see the contents of the non-Error object in question in the `__serialized__` entry of the "Additional Data" section.
To get better insight into these error events, we recommend finding where the plain object is being passed or thrown to Sentry based on the contents of the `__serialized__` data, and turning the plain object into an Error object.