The example solrconfig.xml at solr-8.8.2/server/solr/configsets/_default/conf/solrconfig.xml has the following section repeated twice:
<!-- Use Filter For Sorted Query
I think the duplication might have happened between 8.6.3 and 8.7.0.
It is commented out so there's no impact. Filing as an Improvement rather than Bug given it doesn't break anything.