In Blender’s Freestyle, a line set filters which edges are drawn using criteria like visibility, face marks

https://wikibuilding.org/index.php?title=What_to_Know_Before_Upgrading_an_Older_AC_Line_Set

In Blender’s Freestyle, a line set filters which edges are drawn using criteria like visibility, face marks, and material boundaries, allowing separate stroke styles for silhouettes and creases.