Outliers are removed from A/B tests globally based on the number of searches a user is performing when they are a part of the A/B test.
When calculating metrics such at CTR and CVR for the A/B test variants, we first get all of the searches per user and then check to see if there are outliers. All of the associated aggregates (searches) for the outliers are dropped, and thus all the events related to them are also dropped.
This means if a user is considered an outlier, they won't be contributing to any of the metrics within the test.