Hello Kato and thank you for your response,
I should have sent my request directly to support as it is an feature request.
So I corrected my error by contacting support and have an exchange with Alan (ref:_00D1Ux0Jq._5001URK37x:ref).
For information, it is about that Firebase takes in charge the refresh of the OAuth provider's token.
If my request leads to interesting informations for the Firebase user community, i will do my best to provide the information in this thread.
Thank you and again my apologies for expressing a feature request in the discussion group.