Obtaining TOTP secret from an iOS backup

If you use an iOS device you can use a tool like the iPhone Backup Viewer to extract the secret key.

Open the backup using such a tool
Find the Steam App: com.valvesoftware.Steam in AppDomain
Extract Documents/Steamguard-[your Steam ID]
Open the file using a text editor and look for the text otpauth:\/\/totp\/Steam:[your Steam login]?secret=[TOTP secret]&issuer=Steam.
Copy the value of [TOTP secret] info the TOTP Seed field of the TOTP Setup Wizard.

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