Why are we sending this? We take security very seriously and we want to keep you in the loop on important actions in your account. We were unable to determine whether you have used this browser or device with your account before. This can happen when you sign in for the first time on a new computer, phone or browser, when you use your browser's incognito or private browsing mode or clear your cookies, or when somebody else is accessing your account.
Best, The Google Accounts team
*The location is approximate and determined by the IP address it was coming from.