V$LOGMNR_CALLBACK definition in Oracle Database 11.2
V$LOGMNR_CALLBACK

select
  session_id,                              -- SESSION_ID NUMBER
  function_id,                             -- FUNCTION_ID NUMBER
  description,                             -- DESCRIPTION VARCHAR2(64)
  type                                     -- TYPE VARCHAR2(15)
from
  gv$logmnr_callback
where
  inst_id = userenv('instance')

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