Looking at some of the source code from the MDN site that can be found on GitHub I came across HTM Templates. This was I wanted to know what the double curly brackets were in the source code.
The syntax looks pretty similar to the Template Literals that I also came across in looking are more advanced code.
- Template - not the same thing as this page
- The Mozilla Developers Network
- Template Literals - not sure if this is related
- Timed modal
HTML Templates - January 2021