What is a stellar component?
The term "stellar component" refers to a part ("component") of a system that is in the form of one or more stars.

For example, the Alpha Centauri system has three stellar components: Rigil Kentaurus, Toliman and Proxima Centauri. The planet Proxima Centauri b is also a component of the Alpha Centauri system but it is not a stellar component because it isn't a star.

Another example: the stellar component of a galaxy refers to the fraction of the galaxy that is in the form of stars, as opposed to dust, gas, dark matter, etc.

In the case of your question, it is asking what the inclination would be if the companion were a star (i.e. a stellar component of a binary star system).