I would take this completely literally.
We feel as though logic and formal mathematics really produce or contain meaning, but in fact they just rearrange the meaning we put into them. They are nothing but extremely sophisticated tautologies, and once we have seen the path through them, and gotten the clarity they can help us achieve, we are left with no more meaning than we brought to the table to begin with.
Any meaning they 'produce' in us is not really in them, it is in us. Mathematics and logic are a place where Plato's notion of anamnesis is almost literally correct.
I am not sure that is about any transcendental nature of truth. But it is in its own way deep. It is about the fact that formal language does not contain or confer meaning, it only transfers a point of view from one person to another. This can be useful, but it cannot introduce meaning, it can only point at it.
In his later philosophy, this kind of thinking leads to the characterization of the use of language, especially its formal aspects of grammar and reference, as a 'game' we play in order to communicate, and distinct from the actual act of communication itself.
From my own pet 'neo-Intuitionist' position on mathematics, it confirms that the meaning behind mathematics or logic is not in the formal results but in the intuitions that are already accessible to us, which are used and strengthened by going through the process. Anything you can accomplish by knowing mathematical or logical results is merely a shortcut or an increase in leverage, and is something completely different from what you accomplish by doing mathematics or logic.