From our periscope result ranker module page:

We known that 

info.magnolia.periscope.ResultRankerConfiguration allows you to entirely disable the ranking of Find Bar search results. You may want to use this configuration to improve memory usage or resolve potential compatibility issues with DL4J libraries.

But put in the search bar the term "ResultRankerConfiguration" showing no result. Also we don't know where to put the disable flag! Please help update the documentation of this point.