quick question: if we want to see in an A/B test whether Google or FB traffic performed better, we can create a data-source for this and a dimension, right? BUT: is it also possible to then filter for this for past A/B tests as well or only for those that we start after adding this?

if the data exists, and you just need to add a metric that selects this data, you can add it retroactively to past experiments

thanks for the fast reply 👍

And for your original question, yes, you can add the source as a dimension