The Notes file is for everything that isn't a task to complete. You should list the names of authors that have helped you or have made assets that you are including in or modifying for your addon. You should note where you found assets (usually a web link). You could also note how you solved a particular problem, so you can come back to it later to remind yourself or help someone else.
Create the Notes text file:
Open Notepad++.
Click File > New in the menu.
Click File > Save As... in the menu.
Go to the Setup folder.
Set the File name to: Notes
Click Save button.