The player identifier in rcore_doorlock is used to identify player according to your framework. Used specifically for accessing doors in /doors.
ESX
ESX uses the charid (for example char1:d983f8f701e37ac87c...) as it is in the database in the users table.
How it looks:
QBCore/QBox
QB-Core uses the CItizenID (for example AWT68587) as found in the database table players.
How it looks:
Standalone
Standalone uses license identifier from your FiveM. The type of identifier can be edited in rcore_doorlock/server/modules/bridge/framework/sv-standalone.lua.