@Volker_E After discussing this with the team, I suggest coming in to office hours to help you get the data needed from Superset. I explored the data and put together this dashboard - https://superset.wikimedia.org/superset/dashboard/403/ - so perhaps that meets your needs? The first chart shows the proportion of pageviews from IE11 out of all pageviews - and has conditional formatting to flag where that proportion is above 0.1%

The small variance between Superset data and webrequest data should not affect this analysis. The larger concern is that undetected bot traffic will show up in our user pageview data, but unfortunately we don't have a reasonable way to filter out that traffic right now. We have noted in the past that traffic coming from certain countries (specifically Pakistan, Afghanistan and Iran) are more likely to have inflated bot numbers. And, based on the data I looked at, those are among the top countries for proportion of traffic coming in from IE11.