This RFC explores having MediaWiki allow SVG files to have XHTML namespaces on upload. This was disabled as a result of T62771: SVG iframe XSS. However, legitimate SVG files are also blocked, e.g. the ones produced by draw.io.
Native SVG lacks proper word wrapping support, at least in current implementations, and this can be circumvented by using xhtml and CSS if the displaying application supports that. In case it does not, the less optimal SVG version will be used.
Should be an administrator decision, i.e. a configuration option to turn the xhtml namespace on or off, or one to extend the list of allowed namespaces?
Full RFC: https://www.mediawiki.org/wiki/Requests_for_comment/SVG_Upload_should_(optionally)_allow_the_xhtml_namespace