graph result format can now work with Extension "External Data" and without the defunct Extension "GraphViz". See an example at https://traditio.wiki/%D0%A2%D1%80%D0%B0%D0%B4%D0%B8%D1%86%D0%B8%D1%8F:%D0%9F%D0%BE%D0%BD%D1%8F%D1%82%D0%B8%D1%8F/graphviz.
The necessary settings are:
// GraphViz:
$edgExeName ['graphviz'] = 'GraphViz';
$edgExeUrl ['graphviz'] = 'https://graphviz.org/';
$edgExeCommand ['graphviz'] = 'dot -K$layout$ -Tsvg';
$edgExeParams ['graphviz'] = ['layout' => 'dot'];
$edgExeParamFilters ['graphviz'] = ['layout' => '/^dot|neato|twopi|circo|fdp|osage|patchwork|sfdp$/'];
$edgExeInput ['graphviz'] = 'dot';
$edgExePreprocess ['graphviz'] = 'EDConnectorExe::wikilinks4dot';
$edgExePostprocess ['graphviz'] = 'EDConnectorExe::innerXML';
$edgExeTags ['graphviz'] = 'graphviz';
