per instructions at MediaWiki-extensions-ApiSandbox "New tasks regarding API sandbox should go under the MediaWiki-Action-API project."

So it was quite hastily submitted, here is a better example:

I need to restore a revision for a page:

• I execute an action=query&prop=deletedrevisions query and get a a timestamp like 2020-12-29T00:52:20Z and copy it.
• Then I go to action=undelete and want to paste the timestamp copied. But unfortunately I cannot do it, I see a widget that makes me input the value manually:
  
  • Perfectly there should also be a possibility to insert several pipe separated values, but I think that is a limitation all array like fields inputs have at the moment.