In maintaining a plugin it would be incredibly useful to know of the registered sites using the plugin what version of the plugin or simply Moodle core they are using. Then I'd know what versions would still need supporting / make an informed decision about no longer supporting older versions.

For example, on: https://moodle.org/plugins/stats.php?plugin=theme_essential - I know the number of sites using the plugin and the downloads per version per month (whereby I use a version prefix pertaining to the Moodle major version). If I knew what version of Moodle each site that used the theme was running then that would be very handy!