It seems to miss URLs?

At: https://willadams.gitbook.io/design-into-3d/2d-drawing the links for:

https://mathcs.clarku.edu/~djoyce/java/elements/elements.htm...

https://mathcs.clarku.edu/~djoyce/java/elements/bookI/bookI....

https://mathcs.clarku.edu/~djoyce/java/elements/bookI/defI1....

are rendered as:

_Elements_ _:_ _Book I_ _:_ _Definition 1_

Maybe detect when a page is on gitbook or some other site where there is .md source on github or some other site and grab the original instead?