Listener Question

 I am installing a fresh instance of 11g and importing my 10g database. I noticed differences in the listener file and want ot know if someone can explain the difference.

10g file

LISTENER_EXT =
  (DESCRIPTION_LIST =
    (DESCRIPTION =
      (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC0))
      (ADDRESS = (PROTOCOL = TCP)(HOST = myserver)(PORT = 1521))
    )
  )

SID_LIST_LISTENER_EXT =
  (SID_LIST =
    (SID_DESC =
      (SID_NAME = PLSExtProc)
      (ORACLE_HOME = C:\oracle\product\10.2.0\DB)
      (PROGRAM = extproc)
    )
    (SID_DESC =
      (SID_NAME = NEDSS2)
      (ORACLE_HOME = C:\oracle\product\10.2.0\DB)
    )
  )

11g file

SID_LIST_LISTENER = (SID_LIST = (SID_DESC = (SID_NAME = CLRExtProc) (ORACLE_HOME = E:\Oracle\product\11.2.0\db) (PROGRAM = extproc) (ENVS = "EXTPROC_DLLS=ONLY:E:\Oracle\product\11.2.0\db\bin\oraclr11.dll") ) ) LISTENER = (DESCRIPTION_LIST = (DESCRIPTION = (ADDRESS = (PROTOCOL = IPC)(KEY = EXTPROC1521)) (ADDRESS = (PROTOCOL = TCP)(HOST = myserver)(PORT = 1521)) ) ) ADR_BASE_LISTENER = E:\Oracle My main questions are: 1)What is the difference between CLRExtProc and PLSExtProc ? 2) What is (ENVS = "EXTPROC_DLLS=ONLY:E:\Oracle\product\11.2.0\db\bin\oraclr11.dll")?