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                contao-legacy/au-extauthAuthenticates the user against an external source 
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                contao-legacy/authenticationProvides multiple authentication types to User 
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                contao-legacy/linotp_authUsers can authenticate with a second factor at Contao by connecting contao to LinOTP authentication system. 
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                contao-legacy/au-ldap_authenticationAuthenticate back-end users against an external LDAP service.