Saved hotbar allows for storing containers with large NBT data

VERY closely relates to 

1. MC-114692.

1) Get a chest.

2) Fill a chest with items - preferably written books with lots of data

3) Cntrl + Pick block this chest

4) Place another chest and fill this chest with chests from step 3

5) Repeat multiple times

6) Save into hotbar

7) Join any creative mode server

8) Get the chest with large NBT data from the saved hotbar

This can also be used to potentially bypass server-side restrictions from

1. MC-114692