Looking for logging into the Firebase Custom site and are not getting the correct working link for it? In such a case, you can use the links given here by searching your desired login page in the search box. If the page is present on our website then you will get all the links related to the Firebase Custom site. After that you can login as usual with your login credentials.
https://firebase.google.com/docs/auth/web/custom-auth%3Fhl%3Did
https://firebase.google.com/docs/auth/admin/create-custom-tokens
https://firebase.google.com/docs/auth/android/custom-auth
https://www.youtube.com/watch%3Fv%3DNLWHEiH1FZY
https://www.youtube.com/watch%3Fv%3D7Yc3Pt37coM
https://medium.com/%40AdamRNeary/firebase-custom-authentication-with-no-backend-736c016ed433
https://github.com/FirebaseExtended/custom-auth-samples
https://stackoverflow.com/questions/46023532/how-to-implement-firebase-custom-authentication-backend
https://howtofirebase.com/mildly-secret-custom-claims-58d7ff930e06
https://www.npmjs.com/package/firebase-login-custom
http://firebase.googleblog.com/2016/11/authenticate-your-firebase-users-with-line-login.html
https://firebase-php.readthedocs.io/en/stable/authentication.html
https://www.letsbuildthatapp.com/course/Firebase-Social-Login