Hello @LoriAyn I'm not sure but it sounds like you might have seen an "Internet Traffic" tool referenced somewhere specific to the MX Security Appliance? The tools you see on the "Tools" page are just basic utility programs like ping, DNS, traceroute and to test the throughput of Dashboard connectivity (not the throughput of the MX itself) among other items. There is not an "Internet Traffic" tool that can be run from that page. However, the MX does of course fingerprint and characterize all traffic and clients that it sees, which is easiest to get to on the Network Wide > Clients page, from the pie chart and the customizable flex table, as well as clicking the More link under the pie chart and then clicking into individual applications, or alternatively clicking into a specific clients page to see traffic characteristics for a specific client. There's more you can do from there with filtering, such as viewing any/all clients with a specific policy applied and things like that.
Perhaps you are thinking of a separate product, that runs in conjunction with the MX appliance, called Meraki Insight. MI is all about web application performance, which is exactly what you might be after when you say "Internet Traffic" analysis. MI is a separately licensed product and leverages the MX as the "probe" device, and provides very deep insight into the traffic patterns and performance of any/all web-based apps on your network, and very simple analysis and troubleshooting when issues arise. More info on that here https://meraki.cisco.com/products/insight/
Hope that helps! Let me know if I misunderstood your question.