Understanding Compatibility View / Mode in every version of IE

Question

Can someone please provide a concise explanation of what compatibility view / mode does exactly in each version of IE? (if it's different with each version)

My understanding was that putting your site in compatibility view makes it so that site runs in the previous version of IE. Is that true? Is compatibility view the same as compatibility mode?

What's the difference between having my site in the compatibility view list v.s. changing the setting in my IE dev tools to emulate one version or another?

Let me provide you a scenario for clarity (hopefully).

We have an old web app that needs to run in IE 7. We run IE 8 in compatibility view and it works. We have some SharePoint sites that need to run in IE 8 + with no compatibility set.

My thought is that if I add my old web app to the compatibility view list, but NOT my SharePoint site.. I am still running my SharePoint site without compatibility.

Answer 1

The super documentation of MS: Compatibility View

The compatibility view, automatically detect the version of the page and run it in the best way.
By other hand, the developer tool (F12), force the default version in which you want to view the page.