https://marketsquare.github.io/robotframework-browser/Browser.html#New%20Context
=> see "tracing"
New Context locale=en-US tracing=trace.zip
OR
ROBOT_FRAMEWORK_BROWSER_TRACING=trace.zip
rfbrowser show-trace path_to_trace_Browser.zip
Open a series of traces:
for trace in trace_*.zip; do rfbrowser show-trace $trace ; done