network-manager-config-connectivity-debian 1.12.4-1ubuntu1 (amd64 binary) in ubuntu cosmic

 This package contains a configuration file which enables NetworkManager's
 connectivity checking functionality.
 .
 NetworkManager will try to connect to a Debian server to determine the
 connection status.
 .
 This is particularly useful for captive portal detection.
 .
 No user data is transmitted in the connectivity checks, but merely contacting
 the Debian connectivity check servers reveals that the user is running a
 Debian(-based) operating system with NetworkManager.