Supplementaries mod has a feature to put books on the ground as decoration, but not applied to modded books like colored books added by this mod. I tried adding tags from supplementaries to colored books with datapack, but it won't work. There could be other thing to do to make it happen.

In the next update separate colored books will be removed and coloring would be done as a vanilla book modification.
But placed colored books would not have correct colors. Although possible, this would require custom rendering, which will make performance worse, and can lead to other bugs as well - which makes it not really worth it. Same story with Chiseled Bookshelves.

Oh okay XD

blast!

I'm not worried about accurate colors of placed books. It
won't even let me place it when I add it to the supplementaries "placeable_books" tag

@MinecraftGuy926
From a quick look at supplementaries code it requires specific support in code to be able to place custom books, if I'm not wrong.

1.1.0 removed Scholar colored books in favour of vanilla book coloring. All books should be placeable as usual.
But making placed books have proper colors is much harder and would have worse performance, so it's not planned.