/guide/components/events.md
https://github.com/vuejs/docs/blob/1faadee96301601b7b0e9bd022bea2331a573d0b/src/guide/components/events.md?plain=1#L225
avoiding edge cases caused by DOM events manually dispatched by 3rd party code
https://github.com/vuejs/core/issues/27
The problem is that these same listeners can also be triggered by custom events - in the above example, both a native click event and a custom one emitted by this.$emit('click') in the child will trigger the parent's foo handler. This may lead to unwanted behavior.
I don't quite understand why edge cases are caused by 3rd party code manually dispatch event? If declare the events in emits option, should the events only manually dispatched by code be the target's behavior?
I don't really understand what that means either. I'm not sure it's necessary to mention that edge case to explain the emits option.