This extension enables you to show a text in a box in the bottom right of a website. You can specify on which websites the information needs to shown by using a regular expression for the hostname (so you can also show it on any website by using the expression .*).
Per domain you can configure which text needs to be displayed (like website IP, content of HTTP response headers, HTTP response code, etc - see extension options for all possibilities).
Also, the style of the block is configurable on a per-domain basis, using CSS so you can change anything you like, from font size to color to position, you name it!
The default configuration will just change the IP of the website you visit on a gray background, but you are free to change the configuration to anything you want.
The configuration is pure JSON, so it's easy to copy/paste parts and share your configuration with friends and/or colleagues!