As you know that PWA doesn't show install banner in Facebook in-app browser. So your users don't know that your app can be installed while they visit your PWA Link using the facebook in-app browser.
So we have developed a PWA Popup for Facebook that will encourage & educate users to open your PWA link in Chrome or Safari browser.
We have given options of customization of popup text, display app name, display icon, overlay etc in our PWA Generator.
Default Popup Text: Just tap ••• shown at top right corner and select Open in Chrome / Safari browser & easily add it to your homescreen for an app like experience.