"At least one of the un-Veiled Earths has its own Vatican, so..."
There are three classes. They are 'red', 'green', and 'blue'. The green one has a lot of other nodes connected to it, some in groups and some alone, with other things tied to them. But the first one she touches is blue. It feels studious, and while she's touching it, she can see some of the larger web off in the distance shade bluish, and feel easier to reach, smaller dots becoming less distant. There are two big clusters of complicated webs, and about half of the larger one pulls closer. These feel cerebral, orderly, and so does the 'blue' node itself.
"This is Academic witchery. Academics improve their magic by study and experimentation, a lot like a science class."
Besides the feeling of focus and understanding, mapping out reality in your mind slowly every day, Rebecca can feel a sense of shortcuts and optimization - doing more with less, whether with the (hypothetical/prophetic) feeling of watching a steel cauldron boil or one of carefully writing symbols into leather and silver with gold dust and incense, or of planning out a portal or ripping a fragile one into the air quickly.
"The shortcuts this is trying to show you manifest as doubling what you make, or halving one of the costs you spend to get it. Time or mana, usually. It only applies to things that have a strong tie to academic magic, but that covers a lot of the stuff that gets traded around."
Also, she can feel two dim lines trailing from the cluster, ready to reach out to anything, filling the whole of a complex branch. But it wouldn't be a normal connection, in some abstract way.
"That one's hard to understand. Basically, it gets you two types of magic, mastering it to the limit of your capabilities with no cost from your natural energy, but they still will take just as much time to learn. That's probably about three years of dedicated study for each."