If anyone has a similar requirement, I created a simple script that can be pasted to Greasemonkey/Tampermonkey, here is a link to the gist.
Works with NER manual/make-gold recipes. It extracts a value from the current example’s meta data and creates a link (in my case for youtube), dynamically extracts the currently marked labels and creates a Google search URL for them, then adds these links to a new container added below Prodigy’s display div.
Of course, it may need to be modified for different themes and use cases.
When custom HTML in build-in interfaces will be added, the same technique can be used without Greasemonkey/Tampermonkey.
Note that since the CSS classes in Prodigy’s UI are auto generated, the script will break when they are regenerated (next build?).