If you decide to save the color changes you made with this Add-on for a specific web page/site, the Add-On will save these edits in a Database in your local Firefox profile folder. People which have access to your computer and the right to access the Firefox Browser and files of your local login account will also be able to see these saved color edits and the links to the web sites/pages they are valid on.
You can at any time empty the whole database (and delete all your edits) from the "Color That Site!"-preferences dialogue.
Back to Color That Site!…