This extension disables Private Browsing, hides all the PB menu items and disables the keyboard control. https://addons.mozilla.org/en-US/firefox/addon/disable-private-browsing/

Sorry, it is not possible to remove Private Browsing from Firefox. Never heard of a "Pro" version. AFAIK, both DPB extensions that I do know of are still available from the Add-ons website. ''But both may have compatibility issues with current versions of Firefox, as neither has been updated in a few years.'' https://addons.mozilla.org/en-US/firefox/addon/disable-private-browsing/ https://addons.mozilla.org/en-US/firefox/addon/disable-private-browsing-pl/ And based upon user reviews the "Mobile" (Android and maybe iOS) version has been broken for some time now, so that's why you may not see either in the "Store", they may have been pulled by the developer.