Decades ago, I worked on the XCB library (the replacement for Xlib). I replaced the M4 macros used to generate all the X protocol bindings with XML protocol definitions and XSLT to do code generation.
The XML turned out extremely well, and it's still being used today, such as for bindings in several other languages.
Someone rewrote my XSLT in Python, and I cheered them on, because the result was much more readable, not least of which because the fundamentally procedural steps could be written in a procedural language with a good syntax, rather than XSLT's pure-functional language that suffered from being embedded in XML.
The XML turned out extremely well, and it's still being used today, such as for bindings in several other languages.
Someone rewrote my XSLT in Python, and I cheered them on, because the result was much more readable, not least of which because the fundamentally procedural steps could be written in a procedural language with a good syntax, rather than XSLT's pure-functional language that suffered from being embedded in XML.