Making technical jargon understandable!
Also referred to as the hotdog menu or three-line menu. The hamburger menu is especially useful on mobile devices as makes it easier to view the different menu options, while taking up less real estate.
A sandbox is a development or testing environment. When websites are developed or tested in a sandbox environment, it isolates untested code changes, upgrades, and experimentation from the live environment or website.
New development, testing, etc. can safely be done in a sandbox environment without your website visitors getting affected.
Call to Action (CTA)
It is a piece of content intended to make your website visitor take a certain action. A CTA needs to be the main action you want your visitor to take on a particular page, e.g. subscribe to your newsletter, buy a product, contact. Almost every page needs some kind of call to action.
A call to action should stand out from the rest of the page content. This makes it easy for a visitor to take the desired action.
Mixed content occurs when the initial HTML is loaded over a secure HTTPS connection, but your website has resources such as images, videos etc, that are being loaded over an insecure HTTP connection.
When this happens the browser bar will not display the usual Lock symbol on the browser bar.
Normally your website browser bar should appear like this: