I could not find better place to ask for this, please forward if appropriate.

How is it possible to limit search by topic in answers.atlassian.com now? Previously, there was such possibility, searching by tags, now when it is powered by Confluence, it's not possible to narrow down search results by topic in UI or REST.

Note, I'm particularly interested in REST interface, previously the following worked quite well:

https://developer.atlassian.com/rest/answers/1.0/search?query=test+something&tags=addon-jira-timesheet-plugin

Now, the following does not narrow down search result by topic:

https://answers.atlassian.com/rest/questions/1.0/search/?type=question&query=test+something&topics=addon-jira-timesheet-plugin

Note, this rest endpoint does not correspond to documented /rest/api/content/search confluence rest api. Is there corresponding rest documentation for answers.atlassian.com powered by confluence?

Thank you.