The HTTP Protocols column provided in the "Sites" widget of the "Web Performance" dashboard, lists all HTTP protocols used by corresponding HTTP-Tracers.
When a line of data in a table corresponds to multiple HTTP protocols used, then these protocols are listed by order of occurrence.
In the picture above, the majority of the tests were performed with HTTP/2, but some others were using HTTP/1.1.
If you want to clearly differentiate between the two and get the details per HTTP protocol, simply click on the icon at the top of the column.
The picture below shows the details per HTTP protocol for Testers located in North America.
The line containing a "N/A" in the HTTP Protocol column corresponds to unsuccessful transactions (0% availability and no HTTP transaction performed correctly).