[0] I am not sure what are the, possibly subtle, concerns to trigger the question.
"what is the proper term for attributes (a list of individual attribute) inside the <XML> tag"
They are called attributes, would they not?
[1] In xml recommendation, attributes can appear only within the start-tags or those self-closing empty tag. These are the productions in this regard:
ref http://www.w3.org/TR/REC-xml/#NT-AttlistDecl
[40] STag ::= '<' Name (S Attribute)* S? '>' [WFC: Unique Att Spec]
[41] Attribute ::= Name Eq AttValue [VC: Attribute Value Type] [WFC: No External Entity References] [WFC: No < in Attribute Values]
[42] ETag ::= '</' Name S? '>'
[1.1] An attribute is characterized by its name and value and value type. They should all the same satisfy some well-defined formation rules. And, for a non-validating xml parser, the value types are considered as CDATA. For any xml parser, before values are passed on to application, they should further be normalized with well-defined rules. Things can be slightly more complicated in detail as the recommendation is conceived to satisfy all sorts of concerns from different interested parties at the time as you certainly know.
[2] There isn't anywhere else in an xml instance document the notion of attribute can appear.