AndOTP : Import works, but without labels. You will have to edit them manually.
WinAuth : Import works flawlessly.
For Adding Steam : You have to click the edit button, Then copy/paste your "secret" from Unencrypted WinAuth or AndOTP backup.
For Steam users : You need a rooted android phone and Winauth / SDA.
Check instructions here: https://steamcommunity.com/sharedfiles/filedetails/?id=581563653
https://github.com/Jessecar96/SteamDesktopAuthenticator
Using WinAuth to setup Steam is by far the easiest method. You still need a phone to recieve SMS. Once setup in WinAuth, you will be able to use your "Secret" key to add it to "Authenticator for FF/Chrome".

Thank you for this great add-on!