v2 of the Page Previews enwiki and dewiki A/B test was started at roughly 1 PM UTC on Wednesday, 18th October. It should be stopped on Thursday, Nov 16th, after we have collected four full weeks of data (see T178500#3729981).
Per T178500#3728898, we'd prefer not to disable the feature for those logged-in users who currently have it enabled via their preferences. This is actually fairly simple as @Jdlrobson added an instrumentation killswitch to the Page Previews codebase.
- Deploy a change setting $wgPopupsEventLogging to false.