"But what are you going to do with it [= dragon’s egg] when it's hatched?" said Hermione.
"Well, I've bin doin' some readin', said Hagrid, pulling a large book from under his pillow. "Got this outta the library –– Dragon Breeding for Pleasure and Profit –– it's a bit outta date, o' course, but it's all in here. Keep the egg in the fire, 'cause their mothers breathe on ‘em, see, an' when it hatches, feed it on a bucket o' brandy mixed with chicken blood every half hour. An' see here –– how ter recognize diff'rent eggs –– what I got there's a Norwegian Ridgeback. They're rare, them."
(Harry Potter and the Sorcerer's Stone)
It looks like ‘all’ is a predicative complement over ‘it’. Yet I don’t find such usage in dictionaries. How do I see the ‘all’?