XML
Extensible Markup Language is a markup language and file format for storing, transmitting, and reconstructing arbitrary data. It defines a set of rules for encoding documents in a format that is both human-readable and machine-readable. Wikipedia
So each developer, app can/will have own unique formats.
Apple for example uses a document type ozml for (current) Motion files, fcpxml for FCP, a xmeml for FCP legacy (FC Studio) - latter can be used by PremierePro despite being an Apple format. PremierePro itself uses a XML document type I can't recall this moment - etc.
So there is no "XML type" which can be used across apps and app versions.
If you want to use XML with PPro and FCP you need apps to convert the different XML types in both directions or you need to write a XSLT.
have a look here
https://www.w3schools.com/xml/xsl_intro.asp
Apple Developerdocumentation/professional_video_applications/fcpxml_reference