Why does this example require Observable when it's not used?

General
1

On this page:

How come the Observable is required in but explicitly NOT used?

Is there some type of implicit “magic” going on?

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file942×576

2

That particular example does not need the require(). It should be removed from there.

Unrelated to the require(), there is some implicit magic going on - all properties passed to components are implicitly available as derived Observables in JavaScript as this.varName.