The Solr query for a facets filter click is similar to a query for the overall page. It just adds a filter parameter to the JSON request.
The syntax is filter: "facet:facetfilter", where the facet is the facet ID and facetfilter is the filter string. The facetfilter string will likely have a space, and spaces need to be escaped, e.g. filter: "environment:Epic\ Hyperspace".
The filter JSON parameters can be strung together in an array, so the whole JSON might look like this:
