You can access it in the left menu after logging in. Of course, only Google News publishers have access to this tool.
Stacie explained that "the troubleshooting tool gives you more visibility into the extraction process. It enables you to test on-demand if a specific article can be extracted correctly, or is generating an “Article too long” error, for example. The errors returned can help you towards a fix, which means you can avoid running into crawling issues in the future."
"As always, all outputs from the troubleshooting tool are test data. They will likely be close to what you will see live, but you may see some discrepancies. You can additionally view these news-specific crawl errors in Search Console," she added. But not always do the errors match between the trouble shooter and the Search Console, based on my tests.
Here is a screen shot of a successful crawl:
Here is a screen shot of an error:
This may help some Google News publishers fix their articles after they publish them for Google News.
Forum discussion at Google News Help.