Hook to attach custom data

[groenroos]

Would it be possible to introduce a way to add custom data to be passed to each error (whether JS or PHP)?

Since it's fairly niche, I reckon a simple filter would be sufficient for this (i.e. no need to expose a settings UI in the admin), something that would allow me to do something like:

add_filter( 'raygun_custom_data', function( $error ) {
  return [ "foo" => "bar" ];
}

This would help with important additional developer context; e.g. if #43 becomes possible, I might still wish to capture the WordPress core version as custom data.

[QuantumNightmare]

Thanks for these feature requests - as mentioned on #43 I've written them up for prioritization.