I have observed some linux distribution have
/etc/wpa_supplicant/wpa_supplicant.conf which can be configured to setup WiFi.
On the other hand some distributions have connmanctl utility/tool.
Where we have /var/lib/connman/<SSID>-psk.config file.
Can someone explain the difference between these two and who exactly uses these files to make wifi work?
connman is a network configuration tool such as wicd, netctl or NetworkManager.
wpasupplicant is a supplicant that allows wpa authentication (and more) even with connmanctl.