Discussion in https://github.com/jenkinsci/jenkins/pull/1163 suggested creating an extension point that would let plugins add something to the display of Plugin Manager tabs, probably a new column (such as release date, or installation count). Following the style of NodeMonitor or ListViewColumn, the SPI might allow the plugin to specify whether the UI should be shown by default or not (if there is an option to not show it then there would need to be a way to customize what is shown); views for the header and body cells; and control over which tab or tabs (Updates, Available, Installed) it is shown in.