Special:BannerAllocation (the "Allocation" tab from the CentralNotice admin interface) displays which campaigns and banners may be shown to users for a given project, language and country, at what rates. (See, for example, current allocations for English Wikipedia in Canada.)
However, since the creation of the "Impression diet" and "Large banner limit and switch" features, the data shown has become less reliable and less relevant. (It doesn't consider when "Impression diet" might hide a campaign, and doesn't show that buckets may be unevenly assigned, even though "Large banner limit and switch" moves most users out of buckets A and B quickly.)
Let's adapt this page to current (and planned) CN functionality, considering current and potential use cases. The intent of the page--to provide a quick overview of what a specific segment of users are shown--is surely valid. We should also consider this together with other CN analytics improvements (see T124132).