The double curly braces represent interpolation. It is a special syntax. Angular converts it into property binding. You can think of it as an alternate for property binding. The name of the component is written inside the inner curly braces. During execution, the name is replaced by the actual string value of the property. For example,
<h2> {{apptitle}} <img src="{{imgname}}" style="height:30px"> </h2>
Angular will evaluate and replace apptitle and imgname with their actual values.
