The Library is a giant multi-floor residence, museum and library where Bow grew up with his parents and 12 siblings. Bow has a room there and a little corner where he played pretend historian as a little boy.
Bow was supposed to take over it, but left to work for the Rebellion instead. It's located in the Whispering Woods and has a large staircase, a piano, a grand collection of books, and a fire place.
It was where the Best Research Squad started.
The Library is full of First Ones' tech, including the Colonia Pitcher, a tablet dates back over two millenia, a runestone shard, and a vase with She-Ra riding a dragon on it. The oldest part of their collection is a shard from an ancient, defunct runestone. If it wasn't of historical value, that thing would be long gone.
George and Lance are sad to keep a reminder of the Princesses and their war here, however, they seem to be in better spirit after learning of Bow's fighting in the Rebellion. A bit of damage was done due to the accidental releasing of a First Ones creature, however, thanks to the library's curators, George and Lance, it appears to be remaining in well condition.