private static String getStorageName(String propertyFileName) {
		if (!propertyFileName.endsWith(PROPERTY_EXT)) {
			throw new IllegalArgumentException("property file name must have .prp file extension");
		}
		return propertyFileName.substring(0, propertyFileName.length() - PROPERTY_EXT.length());
	}
Construct an existing PropertyFile.
@param file
@throws FileNotFoundException if property file does not exist
@throws IOException if error occurs reading property file
Ghidra/Framework/FileSystem/src/main/java/ghidra/framework/store/local/IndexedPropertyFile.java