Sprint Goal - Query

While you try to analyze the Scrum Guide to the one sentence, remember also about the whole picture. Here you have a few other quotes that may help you with clarifying your doubts:

The Product Backlog is an ordered list of everything that is known to be needed in the product. It is the single source of requirements for any changes to be made to the product.

and:

The Sprint Backlog is the set of Product Backlog items selected for the Sprint, plus a plan for delivering the product Increment and realizing the Sprint Goal.

In the entire part about Sprint Planning, you find sentences that link to the above statements. Also, consider this sentence from the Daily Scrum description:

The Development Team or team members often meet immediately after the Daily Scrum for detailed discussions, or to adapt, or replan, the rest of the Sprint’s work.

We could sum this like this:

The Sprint Backlog is barely a reflection of our understanding of what we forecast as needed from the Product Backlog at the time when the Sprint Planning happened, in order to achieve the Sprint Goal. The Sprint Goal, on the other hand, gives us a purpose, a context, and a meaning for running the Sprint. Therefore, we achieve our Sprint Goal by implementing things from Product Backlog.

Also, the Scrum Guide loosely refers to Sprint Backlog as a plan, and as is stated in Agile Manifesto:

Responding to change over following a plan

When you will think about it further, during the Sprint, while we strive to achieve the Sprint Goal, we could uncover other things that were unknown prior to Sprint Planning, and as we may assess them as needed in the product, they become a part of Product Backlog, that we could implement in order to achieve this Sprint Goal. Of course, in life, this often does not take such order of actions, but regardless if it is shortcutted because of used tools, of organization context, this distinction is still there.

Hope this helps you a little ;)

In addition to Piotr's answer, I'd also add that the Sprint Backlog "includes at least one high priority process improvement identified in the previous Retrospective meeting". In my experiences, the Sprint Goal relates to the work being done to improve the product and not the team's processes.

I do think that there may be an opportunity to improve the sentence that you quoted from the Scrum Guide, however:

The Sprint Goal is an objective that will be met within the Sprint timebox through the implementation of the Product Backlog Items selected for the Sprint.

But I think it should be, "The Sprint Goal is an objective that will be met within the Sprint through the implementation of the "Sprint" Backlog (and not the Product backlog) .. 

From your reading of the Sprint Planning section in the Scrum Guide, in what context is the Sprint Goal formulated?

Is it:

"Topic One: What can be done this Sprint?"

Or:

"Topic Two: how will the chosen work get done?"

This might explain why reference is made to the Product Backlog rather than the Sprint Backlog.

Thanks @Piotr Górajek for the detailed explanation - it does make sense !

Thanks @Thomas Owens ... I like the improvement you suggested !

Thanks @Ian Mitchell It does make sense ! :)