This warning will not cause an issue when filing your report because it is an issue pertaining to certain validators. It occurs when an XBRL validator isn't able to identify the correct name for the Extension Taxonomy Linkbase in question.
The Extension Taxonomy Linkbase file with a name ending in "_ref" is used for storing references to certain regulations. In most cases the file will be empty, simply because there are no references from the extensions.
When the file contains no information the validator cannot check what type of file it is and because of that it is not able to confirm that the name is correct. This is what causes the warning.