Pretty straightforward solr configuration used for ptsearch.
See branch solr-tomcat for the pre-solr8 configuration.
The cilent code expects XML responses; thus in the solr8 branch the search handler needs to have that set as a default, since more modern solrs default to json.
The pt code expect hl.tag.pre and hl.tag.post to use
{lt:} and {gt:} instead of < and >, as see in the solrconfig.xml file.