Indeed. Although XML has a grammar its complexity led to countless flawed implementations. The original sin of XML is that it has been over-hyped from the begin

Indeed. Although XML has a grammar its complexity led to countless flawed implementations. The original sin of XML is that it has been over-hyped from the beginning. Is it the cause or the consequence of it being over-engineered, I would not say. Anyway following standards, XLST, XPath, saw poor adoption. I am not fond of JSON and YAML either, but since they are much less ambitious, I am somewhat more forgiving with them. None of them is good at being a config file format. None one them is good at data serialization, that should be binary and TLV encoded.