Conversion of snb files to text file format

In case you are looking just for a way to export just the text (and save it as .txt) from older Galaxy S Note notes (.snb), the best think you could do would be to download the S Note for desktop from Samsung website and use it to export snb to pdf (you need to first import the .snb file with the default the File ► Import ► S Note files function). Once that is done, exporting the text from the PDF file should be very easy to do, the quickest would be most likely to just simply copy and paste it to Notepad.

Open SNB file    Open TEXT file