Tom J Nowell

An easy way of telling apart different installs of WordPress ( e.g. live/production/local ) via the admin bar. Super admins see a colour coded machine name in the admin bar, with an IP submenu. Mobiles will see a colour coded square dot

Local Indicator

A fast way of seeing which machine a WordPress install is running on.

Brian Alexander

Adds the current page’s template name to the admin bar.
Because this plugin reveals potentially sensitive information about the active theme, it is recommended for development environments only, and should not be enabled on a production site.

What Template

Adds the current page's template name to the admin bar.

Local Indicator vs What Template