No character encoding was specified

The XML document doesn't declare a character encoding. According to the standard it will be treated as UTF-8, but this may not be correct.

If the document uses something other than UTF-8, you must add an explicit declaration as the very first line of the document:

<?xml version="1.0" encoding="encoding-name"?>

where encoding-name is windows-1252, iso-8859-1, or whichever encoding the document is written with. If this is a perfectly valid UTF-8 document, adding the declaration avoids ambiguity.

If you are not sure what encoding your tooling uses, following the instructions in the Survivial Guide to i18n