What is OPTSTAT_HIST_CONTROL$ table?

"OPTSTAT_HIST_CONTROL$" table. When I found out about it. I only know SNAME and SPARE4 columns.
SQL> select SNAME, SPARE4  from SYS.OPTSTAT_HIST_CONTROL$;

Anyway, How can I find out more information about this table? I mean Information for each column.

SQL> desc OPTSTAT_HIST_CONTROL$
 Name                                      Null?    Type
 ----------------------------------------- -------- ----------------------------
 SNAME                                              VARCHAR2(30)
 SVAL1                                              NUMBER
 SVAL2                                              TIMESTAMP(6) WITH TIME ZONE
 SPARE1                                             NUMBER
 SPARE2                                             NUMBER
 SPARE3                                             NUMBER
 SPARE4                                             VARCHAR2(1000)
 SPARE5                                             VARCHAR2(1000)
 SPARE6                                             TIMESTAMP(6) WITH TIME ZONE