I wanna preface this by saying that I have 0 oracle database knowledge and right now I am facing the following issue:

At my job we used to build custom oracle db docker images using rpm files and creating the listener.ora files ourselves in a sort of legacy system. An example of the old config is this for the oracle database 19 version:

DEFAULT_SERVICE_LISTENER = ORCLCDB

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = TCP)(HOST = 0.0.0.0)(PORT = 1521))
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521))
    )
  )
SID_LIST_LISTENER=
  (SID_LIST=
    (SID_DESC=
      (SID_NAME=ORCLCDB)
      (ORACLE_HOME=/opt/oracle/product/19c/dbhome_1)
      (PROGRAM=extproc)))

Now I am using the oracle database 23ai FREE and this is what the listener.ora file looks like:

SID_LIST_LISTENER =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = /opt/oracle/product/23ai/dbhomeFree)
      (PROGRAM = extproc)
    )
  )

LISTENER =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC_FOR_FREE))
      (ADDRESS = (PROTOCOL = TCP)(HOST = 0.0.0.0)(PORT = 1521))
    )
  )

DEFAULT_SERVICE_LISTENER = (FREE)

I have tried to understand what the differences are by reading this manual but I am going to be honest, I really dont understand so much the difference. Will using SID_NAME = PLSExtProc disallow me doing normal database operations? Does anyone know where I could find documented what PLSExtProc is? Additionally I tried to find what EXTPROC_FOR_FREE equates to and I am not sure where to look, is this a default environment variable?