@scottalanmiller is correct, those numbers are produced on the fly based on active websocket sessions, and not stored anywhere.
However, you might be interested in
Adds browsing users to topics. Contribute to barisusakli/nodebb-plugin-browsing-users development by creating an account on GitHub.
faviconGitHub (github.com)
, which brings a live-list of current users in-topic back to topic.tpl 😄
