that's why it's called wallet dump
basically each line represents info of a specific bitcoin address
# addr= hdkeypath=

Quote from: ironfeast on October 11, 2018, 05:57:17 PM

Could anyone explain me how to export and import bitcoin's private keys in bitcoin core.

depending on your intentions, there are a few dos and don'ts on exporting/importing keys
and there are a few commands that you can use:
dumpprivkey: exports single private key of an address
dumpwallet: exports all private keys to a file in wallet dump file format
importprivkey: imports single key into bitcoin core  
importaddress: imports a watch-only address
importwallet: imports private keys from a file in wallet dump file format

tell us your specific intention, so we can give you advise on how to do it properly and safely