Missing xml-model reference generates multiple similar warnings

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Try to open this (file.xsd is obviously missing)

<?xml version="1.0" encoding="UTF-8"?>
<?xml-model href="file.xsd" type="application/xml" schematypens="http://www.w3.org/2001/XMLSchema"?>
<classpath>
	<classpathentry kind="src" output="bin/main" path="src/main/java">
		<attributes>
			<attribute name="gradle_scope" value="main"/>
			<attribute name="gradle_used_by_scope" value="main,test"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="src" output="bin/main" path="src/main/resources">
		<attributes>
			<attribute name="gradle_scope" value="main"/>
			<attribute name="gradle_used_by_scope" value="main,test"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="src" output="bin/test" path="src/test/java">
		<attributes>
			<attribute name="gradle_scope" value="test"/>
			<attribute name="gradle_used_by_scope" value="test"/>
			<attribute name="test" value="true"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="src" output="bin/test" path="src/test/resources">
		<attributes>
			<attribute name="gradle_scope" value="test"/>
			<attribute name="gradle_used_by_scope" value="test"/>
			<attribute name="test" value="true"/>
		</attributes>
	</classpathentry>
	<classpathentry kind="con" path="org.eclipse.jdt.launching.JRE_CONTAINER/org.eclipse.jdt.internal.debug.ui.launcher.StandardVMType/JavaSE-1.8/"/>
	<classpathentry kind="con" path="org.eclipse.buildship.core.gradleclasspathcontainer"/>
	<classpathentry kind="output" path="bin/default"/>
</classpath>

See the multitude of schema_reference.4: Failed to read schema document 'untitled:file.xsd', because 1) could not find the document; 2) the document could not be read; 3) the root element of the document is not <xsd:schema>. warnings: