Update 0035-metadata-csv-utf-8-file-validation.md

architecture-decision-records/0035-metadata-csv-utf-8-file-validation.md

@@ -20,7 +20,7 @@ The structure and integrity of the CSV file is checked before the actual [data i
 The metadata csv files are prepared by the transferring body, and it is expected **Microsoft Excel** will be used and users can be required to save with the UTF-8 option.  
 Files stored in this manner will add the BOM
 
-The tdr-draft-metadata-validator will use the presence of the BOM (Byte order mark) at the beginning of the file. This indicates the file may have been created with **Microsoft Excel** and explicitly saved as UTF-8.  
+The tdr-draft-metadata-validator will use the presence of the BOM (Byte order mark) at the beginning of the file. This indicates the file may have been created with **Microsoft Excel** and explicitly saved as UTF-8. This is a simple and fast check that only for the first three bytes 'EF BB BF'  
 This method is restrictive as other spreadsheet software such as LibreOffice (Linux) and Numbers (Mac) do not add the BOM
 
 TNA CSV validator uses TNA utf8-validator library. This library checks the byte sequence and invalid single bytes. It does not check the BOM that suggests a file saved explicitly saved as UTF-8 from Microsoft Excel