The dashboard is found at:
/modules/jrCore/templates/dashboard.tpl
So its over-rideable at skin level by copying it to:
/skins/(YOUR SKIN)/jrCore_dashboard.tpl
and changing it.
The process is documented here:
"Altering a Modules Template"
https://www.jamroom.net/the-jamroom-network/documentation/development/1051/altering-a-modules-template
If you want to add to it in the same way that the stuff there is put there, take a look at:
/modules/jrCore/include.php around line 449
jrCore_register_module_feature('jrCore', 'dashboard_panel', 'jrCore', 'queue depth', 'jrCore_dashboard_panels');
jrCore_register_module_feature('jrCore', 'dashboard_panel', 'jrCore', 'memory used', 'jrCore_dashboard_panels');
jrCore_register_module_feature('jrCore', 'dashboard_panel', 'jrCore', 'disk usage', 'jrCore_dashboard_panels');
jrCore_register_module_feature('jrCore', 'dashboard_panel', 'jrCore', 'CPU count', 'jrCore_dashboard_panels');
jrCore_register_module_feature('jrCore', 'dashboard_panel', 'jrCore', 'installed modules', 'jrCore_dashboard_panels');
jrCore_register_module_feature('jrCore', 'dashboard_panel', 'jrCore', 'installed skins', 'jrCore_dashboard_panels');
jrCore_register_module_feature('jrCore', 'dashboard_panel', 'jrCore', '1 minute load', 'jrCore_dashboard_panels');
jrCore_register_module_feature('jrCore', 'dashboard_panel', 'jrCore', '5 minute load', 'jrCore_dashboard_panels');
jrCore_register_module_feature('jrCore', 'dashboard_panel', 'jrCore', '15 minute load', 'jrCore_dashboard_panels');
jrCore_register_module_feature('jrCore', 'dashboard_panel', 'jrCore', 'pending items', 'jrCore_dashboard_panels');