Shelf codes should be more descriptive and spelled out

[Popolechien]

I can sort books by shelf, yet unless I am familiar with LCC classification, I have no idea what I am sorting by (nor probably do I know what LCC means either)

(see here for source)
In the case at hand, we should read Library of Congress Class: Germanic Literature

[benoit74]

Agreed, we even have the strings available in the source code