Currently a search field labeled “Search the web” is displayed. If this page is freshly loaded from the search provider every time Firefox is started, they can make statistics about people’s Firefox usage, which is a privacy leak.
This search input field is not loaded from the search provider but rather just integrated into Firefox.
Thank you for your answer. Is there a way to customize the first tab of a new private session in Firefox?
about:privatebrowsing as the home page for private windows appears to be hard coded when you are opening a private window in a session that started with a regular window.
If you prefer a blank page, you could try using a desktop shortcut to launch that window. For example, on 64-bit Windows, this command line works:
"C:\Program Files\Mozilla Firefox\firefox.exe" -private-tab about:blank
Don’t use the Browse… button, just paste the path and click Next.