The authenticator generates a code that you need to login to your Steam account. The Steam Guard Code changes every thrity seconds and can only be used once to login.

Losing your 2FA codes can be bad. ... With no access to his Google and Microsoft authenticator apps, he lost access to two-factor ... The lack of a backup and recovery mechanism meant ...

According to the announcement, the Steam Guard Mobile Authenticator will hit iOS and Android Steam apps, and will offer "additional ways to protect and recover your account", beyond the ...