Diagnostics
Diagnostics is a tool that can be used to help diagnose the behavior of the search engine with a specific configuration and search phrase, mimicking the search behavior on a live site.
Diagnostics is run on the current unpublished data rather than the live data, to allow users to test the unpublished changes before committing them to the live site.
Pipeline analysis
The pipeline analysis shows how the search engine understands the search phrase and what ends up being searched for. It also makes it possible to analyze how the different rules influence the search engine and see the effect of the text analysis rules, for the current segment.
The documentation for pipeline analysis goes into more detail.
Search results
The search results display all products which would be found by the search phrase. When clicking a product, it shows why that product was matched with the search phrase by the search engine.
Missing products
Missing products allows for comparing a specific product against a search phrase and understanding why the product does not appear in a search.
Combined with the pipeline analysis tool, this can be a great way to find out which modifications are needed in the text analysis rules.