Several components in ADF make use of transclusion, which is the technique of incorporating user-supplied content in the body of a standard component.
In most cases, this is used to make small customizations (for example, the various list components let you supply custom content to show when the list is empty). However, there are also a few "containers" whose entire content is set by the user with the container itself being mainly for convenient display and formatting (for example, the Info drawer component).
You supply the content you want to transclude between the opening and closing tags of the main component. In a few cases, this content can be completely free-form as with the body section of the Login component:
<adf-login ...> <div> <div>Your extra content</div> </div> </adf-login>
More often, though, the main component makes use of one or more sub-components to add structure to the transclusion. For example, the Login component also has sub-components for the header and footer regions in addition to the free-form content of the body:
<adf-login ...> <login-footer><ng-template>My custom HTML for the footer</ng-template></login-footer> </adf-login>
The doc pages for the components that use transclusion contain full details of all supported sub-components and their usage.