nmcli utility, you can get information about Network-Manager's previously-established network connections e.g.
nmcli con list
To limit the output to specific fields of interest, you can do something like
nmcli -f NAME,TIMESTAMP-REAL con list
which lists the connection name and time of last connection. You can also do more specific queries by connection ID or UUID e.g.
nmcli -f 802-11-wireless con list id "NETGEAR68-5G"
(quotes not mandatory unless the name contains spaces or other special characters), where in this case
NETGEAR68-5G is the name of one of the previously-established connections as returned by the basic
nmcli con list command. In this case, the
802-11-wireless field should include SSID, and BSSID if available.