TL;DR
Remember scroll position in a bp book while opening a blueprint.What ?
When you have a large blueprint book, you scroll down in it, open a blueprint and then close that blueprint again, you are back at the start of the book. I would like to be at the exact place I was before.Why ?
Because it can be really hard to find back to the page you just opened. Vanilla supports 1000 blueprints in a book, so this problem is not restricted to mods. If you want to actually work with large blueprint books, this feature would be very welcome.And usually, when I take a closer look at a side of a real book I do not immediatley go back to the first page afterwards. But maybe that's just me.
PS:This refers to the stable version 0.17.79. I am not aware, if this is still the case in 0.18.15.
Edit: It exists in 0.18.15 and I am reffering to scrolling in the blueprint book window, not shift+scrolling while holding the book in hand. That is why i refered to "large blueprint book", as the scroll bar only shows up for a large blueprint book.