Whilst working on a personal project, I discovered the existence of an old version of the XSLT specification, identified by the namespace
http://www.w3.org/TR/WD-xsl instead of the modern
According to this answer on Stack Overflow, this refers to the IE4 implementation of a working draft of the XSLT specification. This implementation differed substantially from the final version and is not compatible.
So that people dealing with this would not have to write XSLT to convert WD-xsl into conforming XSLT, apparently Microsoft wrote a tool to aid the transition. But I can barely find any information at all that isn't just people complaining about WD-xsl.
What information about WD-xsl is there available? A schema? The version of the spec the IE4 team used to implement it? The possibly-fictional tool to convert it into compliant XSLT?