As per jcr spec, whenever a system view is being exported and there are non-binary properties which contain illegal xml characters, they should be exported as: xsd:base64Binary

However, the "xsd" prefix is just a hint :

The namespace mappings for xsi and xsd are added to the exported XML document so that the xsi:type attribute is within their scope.
The namespace declarations required are xmlns:xsd=“http://www.w3.org/2001/XMLSchema” and xmlns:xsi=“http://www.w3.org/2001/XMLSchemainstance”.

Note that the prefixes representing these two namespaces need not be literally “xsd” and “xsi”. Any two prefixes are permitted as long as the corresponding
namespace declarations are changed accordingly.

Currently, when exporting, we're hardcoding the "xsd" & "xsi" prefixes (regardless of what the namespaces uris are mapped to) and when importing, we're not really looking for the xsd:base64Binary type to decode from Base64. However, we are looking for xs:base64Binary, due to MODE-1026.