I couldn't spot a function for this.
The problem is to have a button within each tab that clears the facets but retains the selected tab
All I can see in the documentation is
href="${response.facetExtras.unselectAllFacetsUrl}"
which clears all the facets INCLUDING the tabs
or
href="${facet.unselectAllUrl}"
that just clears facet options within a particular facet
Just wondered if there was a neat way to do this rather than manually constructing the links.