When passivetex.extensions=1 character ​ is inserted between all occurences...

When passivetex.extensions=1 character ​ is inserted between all occurences of --. This stops TeX ligature mechanism which converted all -- to endash and --- to emdash (this is ill especially in source code listings containing XML comments or decrementation operator). Performance cost of evaluating condition for each text node is under 5 %. This shouldn't annoy anyone.