These bags only hold items related to Inscription supplies, but are larger than the average general bag.
“ Inscription Bags are a special type of bag that hold items created by scribes. Types of Bags...Inscription bag
“ Pack of Endless PocketsItem Level 75Disenchants into: Not disenchantableBinds when equipped32...Pack of Endless Pockets
“This item is created with Leatherworking (510): [Pattern: Royal Scribe's Satchel]. Patch changes...Royal Scribe's Satchel