>https://www.w3.org/TR/REC-xml/
>match
>[Definition: (Of strings or names:) Two strings or names being compared are identical. Characters with multiple possible representations in ISO/IEC 10646 (e.g. characters with both precomposed and base+diacritic forms) match only if they have the same representation in both strings. No case folding is performed.
I'm quite fond of XML myself, and this is not an issue in XML.
I mean, yes, the standard says that parsing should be case sensitive (I also found https://stackoverflow.com/questions/7414747). But people parse it as if it were case insensitive all the time, in part thanks to tradition established by HTML. In this case, the XML looked like
and other code would try to filter the messages for presentation. And it appears that even if their spec demanded uppercase tag names, they were case-folding them for lookup purposes (to map "INFO" to some constant like CompilerMessageSeverity.INFO, or something like that).