Imagine we have a web component <foo-component id="fooShadowRoot"> and need to query a sub-element within its Shadow DOM. So we create a target for the foo-component:
Defining shadow root target
Then we create a target for the hosted element
Defining hosted element target
The first one is a simple target like we are used to have in Puppetry, but the second is chained one. While building it we expand Options, set Parent target to SHADOW_FOO and Parent type to shadow host.
Chained target
As soon as the hosted element target defined (SHADOWDOM_FOO_LOCAL) we can address it as any simple target: