Please note: that the following source code is provided and copyrighted by Microsoft and is for educational purpose only.
  The meta data is from an SQL 2012 Server.
  I have posted alot more, find the whole list 
here.
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Definition or 
MetaData    sys.sp_fulltext_service(
nvarchar @action, 
sql_variant @value)    
       create proc sys.sp_fulltext_service      @action     nvarchar(100) = NULL,      @value      sql_variant = NULL  as      set nocount on        --  sp_fulltext_service will run under read committed isolation level --       set transaction isolation level READ COMMITTED        --  CHECK PERMISSIONS (must be serveradmin) --       if (is_srvrolemember('serveradmin') = 0)      begin          raiserror(15247,-1,-1)          return 1      end        --  DISALLOW USER TRANSACTION --       set implicit_transactions off      if @@trancount > 0      begin          raiserror(15002,-1,-1,'sys.sp_fulltext_service')          return 1      end        --  initialize full-text configuration table --       declare @fulltext_configuration_table TABLE (          Name nvarchar(100) NOT NULL UNIQUE,          IsDeprecated  smallint default 0,          IsVisible     smallint default 0,          FNC_Name nvarchar(200),          HasValue      smallint default 0,          Type nvarchar(30) default NULL,          NeedRangeCheck smallint default NULL,          minvalue       bigint default NULL,          maxvalue       bigint default NULL,               dflt_longlong  bigint default NULL,          dflt_str       nvarchar(1024) default NULL)        --  for resource_usage, we set both index and query performance level to the value. So when we read value we just return      --  index performance level. Index and query performance level are suppose to be same. However, user can directly set      --  index and query performance level and they can be different. Resouce usage is just a setting for backward compatibility.      --                                                    name                        depre, visi,FNC_Name                    hasVal, type,     rangechk,    min,    max,    dfltl,    dftlstr       insert into @fulltext_configuration_table values ('resource_usage',             1,    1,     'FTE_IndexingPerformanceLevel', 1,     'int',         1,         0,         0,         NULL,     NULL)      insert into @fulltext_configuration_table values ('clean_up',                     1,    1,     NULL,                             0,     NULL,        NULL,    NULL,    NULL,     NULL,     NULL)      insert into @fulltext_configuration_table values ('connect_timeout',             1,     1,    NULL,                             1,     'int',         1,         0,         0,         NULL,     NULL)      insert into @fulltext_configuration_table values ('data_timeout',                 1,     1,    NULL,                             1,     'int',         1,         0,         0,         NULL,     NULL)      insert into @fulltext_configuration_table values ('update_languages',             0,     1,    NULL,                             0,     NULL,        NULL,    NULL,    NULL,     NULL,     NULL)      insert into @fulltext_configuration_table values ('restart_all_fdhosts',             0,     0,    NULL,                             0,     NULL,        NULL,    NULL,    NULL,     NULL,     NULL)      insert into @fulltext_configuration_table values ('pause_indexing',             0,     1,    'pause_indexing',                 1,     'int',         1,         0,         1,         NULL,     NULL)      --  The following are config values      insert into @fulltext_configuration_table values ('load_os_resources',             0,     1,    'FTE_LoadOSResources',             1,     'int',         1,         0,         1,         0,         NULL)      insert into @fulltext_configuration_table values ('verify_signature',             0,  1,    'FTE_VerifySignature',             1,     'int',         1,         0,         1,         1,         NULL)      insert into @fulltext_configuration_table values ('aggressive_break',             0,     0,    'FTE_AggressiveBreak',             1,     'int',         1,         0,         1,         1,         NULL)      insert into @fulltext_configuration_table values ('ism_size',                     0,     0,     'IFTS_ISMSize',                 1,     'int',         1,         1,         16,     0,         NULL)      insert into @fulltext_configuration_table values ('batch_size',                 0,     0,     'IFTS_BatchSize',                 1,     'int',         1,         100,     10000,     0,         NULL)       insert into @fulltext_configuration_table values ('outstanding_batches',        0,     0,     'IFTS_OutstandingBatches',        1,     'int',         1,         1,         100,     5,         NULL)       insert into @fulltext_configuration_table values ('outstanding_isms',              0,     0,     'IFTS_OutstandingISMs',            1,     'int',         1,         1,         100,     5,         NULL)           insert into @fulltext_configuration_table values ('auto_crawl_end_fragments_merge', 0,     0,    'IFTS_AutoCrawlEndMergeFragments',     1,     'int',         1,         2,         50,     5,         NULL)      insert into @fulltext_configuration_table values ('fdhost_tracing',             0,     0,    'IFTS_FDHostTracing',             1,     'int',         1,         0,         1,         0,         NULL)      insert into @fulltext_configuration_table values ('fdhost_tracing_numberoflogs',0,     0,     'FTE_RetailTracingNumberOfLogs',1,     'int',         1,         1,         500,     10,     NULL)      insert into @fulltext_configuration_table values ('fdhost_tracing_tag',         0,     0,    'IFTS_FDHostTracingTag',         1,     'nvarchar', NULL,     NULL,     NULL,     NULL,     N'')      insert into @fulltext_configuration_table values ('fdhost_dump',                 0,     0,    'IFTS_FDHostDump',                 1,     'int',         1,         0,         1,         1,         NULL)      insert into @fulltext_configuration_table values ('processor_affinity',         0,     0,    'FTE_ProcessorAffinity',         1,     'int',         NULL,     NULL,     NULL,     0,         NULL)      insert into @fulltext_configuration_table values ('crawl_ranges',                 0,     0,    'IFTS_NumRanges',                 1,     'int',         1,         0,         256,     0,         NULL)      insert into @fulltext_configuration_table values ('master_merge_dop',         0,     0,    'IFTS_PmmDop',                 1,     'int',         1,         0,         256,     0,         NULL)      insert into @fulltext_configuration_table values ('ft_timeout',                 0,     0,    'IFTS_FTTimeout',                 1,     'int',         1,         10000,     6000000,60000,     NULL)      insert into @fulltext_configuration_table values ('max_singledoc_retries',         0,     0,    'IFTS_MaxSingleDocRetries',     1,     'int',         1,         0,         10,     1,         NULL)      insert into @fulltext_configuration_table values ('upgrade_option',         0,     1,    'IFTS_CatalogUpgradeOptions',     1,     'int',         1,         0,         2,     2,         NULL)      insert into @fulltext_configuration_table values ('fdhost_dump_flags',         0,     0,    'FTE_SQLDumperFlags',     1,     'nvarchar',         NULL,         NULL,         NULL,     NULL,         N'0x820')      IF SERVERPROPERTY('IsNonGolden') IS NOT NULL      begin          insert into @fulltext_configuration_table values ('mm_partition_count',     0,     0,    'FTE_SQLMMPartitionCount',             1,     'int',         1,         0,         1000,         1000,         NULL)          insert into @fulltext_configuration_table values ('merge_range_size_in_bytes',     0,     0,    'FTE_SQLMergeRangeSizeInBytes',             1,     'int',         1,         0,         100 * 1024 * 1024,         100 * 1024 * 1024,         NULL)          insert into @fulltext_configuration_table values ('costing_factor',     0,     0,    'IFTS_Costingfactor',             1,     'int',         1,         1,         1000000,         1000,         NULL)      end        --  if action is null, we print out all configuration options that are available to user --       if @action is null      begin          select Name as 'configuration name',                 CASE IsDeprecated                 WHEN 1 THEN 'Yes'                 ELSE   'No'                 end as 'is deprecated',                 Type as 'configuration value type',                 minvalue as 'minimum', maxvalue as 'maximum'          from @fulltext_configuration_table          where IsVisible = 1          order by Name          return 0      end        --  utility: list all sp_fullext_service options      if @action = 'show_all'      begin          select Name as 'configuration name',                 CASE IsDeprecated                 WHEN 1 THEN 'Yes'                 ELSE   'No'                 end as 'is deprecated',                 Type as 'configuration value type',                 minvalue as 'minimum', maxvalue as 'maximum'          from @fulltext_configuration_table          order by Name          return 0      end        declare @Name nvarchar(100)      declare @IsDeprecated  smallint      declare @FNC_Name nvarchar(200)      declare @HasValue      smallint      declare @Type nvarchar(30)      declare @NeedRangeCheck smallint      declare @minvalue       bigint      declare @maxvalue       bigint      declare @dfltlonglong   bigint      declare @dfltstr        nvarchar(1024)      declare @sval nvarchar(1024)          --  find configuration option from the table --       select  @Name = Name,          @IsDeprecated = IsDeprecated,          @FNC_Name = FNC_Name,          @HasValue = HasValue,          @Type = Type,          @NeedRangeCheck = NeedRangeCheck,          @minvalue = minvalue,          @maxvalue = maxvalue,          @dfltlonglong = dflt_longlong,          @dfltstr = dflt_str      from @fulltext_configuration_table where Name = @action        --  Check if configuration option is exposed to user or Yukon Style options for mssearch internal use (no longer supported)      if (@Name is null)      begin         --  Yukon Style options for mssearch internal use (MSSearch only) options are not supported anymore       --  It has been decided that we throw an error for most of the MSSearch only options (some options will still be supported)       --  These options are not documented and has not been advertised to general public or CSS.       --  The other option is to make it a no-op for options we no longer support but it was decided (Jingweil and deepakp)       --  that we throw an error for the reasons explained above.       --           raiserror(15600,-1,-1,'sys.sp_fulltext_service')          return 1      end        --  if value is null, we print the option value --       if (@value is null)      begin          --  if the option doesn't have value, we will just run the command          if (@HasValue = 0)          begin              --  If it is deprecated, we will not do anything --               if (@IsDeprecated = 1)              begin                  --  21 logs the usage of the deprecated action and increments                  --  the appropriate perf counter for this deprecated feature                  --                                   DBCC CALLFULLTEXT(21, @Name)                  return 0              end                --  DBCC CALLFULLTEXT (18 ) --               if @action = 'update_languages'              begin                  DBCC CALLFULLTEXT (18 ) --               end          else if @action = 'restart_all_fdhosts'          begin              DBCC CALLFULLTEXT (22 )          end              else              begin                  --  current only update_languages is non-value option                  raiserror(15600,-1,-1,'sys.sp_fulltext_service')                  return 1              end          end          else          begin              --  If it is deprecated, we will print 0 as value --               if (@IsDeprecated = 1)              begin                  select @Name as 'Configuration Name', 0 as 'Configuration Value'                  --  21 logs the usage of the deprecated action and increments                  --  the appropriate perf counter for this deprecated feature                  --                                       DBCC CALLFULLTEXT(21, @Name)                  return 0              end                --  print the configuration name and value              DBCC CALLFULLTEXT(2, @FNC_Name, @Name)          end          if @@error <> 0              return 1      end      else      begin          if (@HasValue = 0)          begin              --  try to set an option which don't take a value --               --  invalid parameter, raise error here --               raiserror(15600,-1,-1,'sys.sp_fulltext_service')              return 1          end          else          begin              --  If it is deprecated, we will not do anything --               if (@IsDeprecated = 1)          begin                      --  21 logs the usage of the deprecated action and increments                      --  the appropriate perf counter for this deprecated feature                      --                       DBCC CALLFULLTEXT(21, @Name)                                      return 0              end                select @sval = convert(nvarchar(1024), @value)          if @@error <> 0          return 1             if (@Type = 'int')          begin              --  convert to int value first --           declare @i bigint          if ltrim(rtrim(lower(@sval))) = N'default'              select @i = @dfltlonglong           else          begin                      select @i = convert(bigint, @sval)                      if @@error <> 0                          return 1              if @i = -1                  select @i = @dfltlonglong          end            --  check if the value is in the range --                   if ((@NeedRangeCheck = 1) and ( @i is null or (not (@i between @minvalue and @maxvalue) and @i <> @dfltlonglong)))                  begin                      raiserror(15600,-1,-1,'sys.sp_fulltext_service')                      return 1                  end                  select @value = @i           end          else               begin          if ltrim(rtrim(lower(@sval))) = N'default'              select @value = @dfltstr          else                      select @value = @sval           end                if @action = 'pause_indexing'              begin                  DBCC CALLFULLTEXT ( 19, @value )  --               end              else              begin          DBCC CALLFULLTEXT ( 1, @FNC_Name, @value) --  Set config value              end              if @@error <> 0                  return 1          end      end        --  SUCCESS --       return 0    --  sp_fulltext_service