Captive portal login

A captive portal is a network access point ie where you enter a password eg connecting to wifi. I can't tell you why it shows up in google activity as I don't know what you do with your phone but that is generally what happens
 
Thank you so much!! Especially for putting it in terms I can actually understand. One more question though, if I used Google while on wifi, would that be the reason captive portal login showed up in my google activity??