Privatefox is described as 'Redirects opened URLs and files from Firefox to Firefox Private Browsing - GitHub - PolicyPuma4/Privatefox: Redirects opened URLs and files from Firefox to Firefox Private Browsing' and is an app in the development category. There are 2 alternatives to Privatefox for Mac and Windows. The best Privatefox alternative is Browserosaurus, which is both free and Open Source.
Browserosaurus is an open-source (MIT license), Electron-based app for macOS. It works by setting itself as the default browser; any clicked links in non-browser apps are now sent to Browserosaurus where it’ll present you with a menu of all your installed browsers.
Redirects opened URLs and files from Google Chrome to an incognito Google Chrome window
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