I’m opening this proposal to improve the interface of TargetableEvent so that it extends RecordableEvent: this is a breaking compatibility change which should have very small impact.
Related JIRA ticket: [XWIKI-19585] TargetableEvent should extend RecordableEvent - XWiki.org JIRA
The reason why I propose that change is because it doesn’t make sense in XS for a TargetableEvent to not also implements RecordableEvent, and the documentation almost says that too.
The only possible impact of this behaviour change, is that if a for some reason a listener should only handle TargetableEvents which are not RecordableEvents. Which IMO is very unlikely to happen.