Are they tabs? Are they spaces? How many? Never wonder again!
- Chrome WebStore: https://chrome.google.com/webstore/detail/ifdbipohclgnokjgpejhnbjdlgjkkhom
- Firefox Add-on: https://addons.mozilla.org/en-GB/firefox/addon/render-whitespace-on-github
Alternatively, you can install this as a userscript.
To install as a userscript in Chrome, save the JavaScript file and drag it onto the chrome://extensions page.
If you use ViolentMonkey, TamperMonkey, or GreaseMonkey, install from one of these links: