browser.privatebrowsing.autostart
You don’t want anyone to have study trails of the things you’ve been browsing online. This Firefox command helps you to prevent people from looking at your browsing information. Leaving footprints on your browser is what you don’t want to happen, especially when browsing scrupulous websites.
When you switch to private browsing, no third party will be able to access cookies or any records or history of websites you have been browsing. However, unfortunately, even though nobody could look at your browsing data on your computer, the ISP will have the privilege of peeping through in your Private Browsing mode. Therefore, you may want some extra protection measures.
At the same time, you should always consider using the private browsing mode even if you are on your own or are the sole user of your laptop because of its cookie-blocking functionalities. You need to set this preference to true, and that switches the Firefox to always start in private browsing mode.