How to find the Database Startup parameters for all login Brokers
Only Primary Broker startup parameters not Secondary Login Broker parameters are listed in the database lg file
Startup parameters are not listed in the database lg file for secondary login brokers
How to find if the startup parameters specified at Database Startup are also used for Secondary Login Brokers?

VST: _Server._SrvParam*

Since OpenEdge 11.5 _Server._SrvParam* fields contain the values of Broker-specific startup parameters, which can be customised to requirement:

DEFAULT-WINDOW:WIDTH = 80 .
DEFAULT-WINDOW:HEIGHT = 32 .

DEFINE VARIABLE iParamCount AS INTEGER NO-UNDO.
DEFINE VARIABLE iExtents    AS INTEGER NO-UNDO.

FOR EACH _servers WHERE _Server-Pid = _Server-Broker-Pid BREAK BY _servers._server-type: /* Only for login brokers */
    ASSIGN iExtents = EXTENT( _servers._srvparam-name).
    DO iParamCount = 1 TO iExtents:
         IF _srvparam-name[iParamCount] NE ? THEN
            DISPLAY
            _Server-Broker-Pid iParamCount _srvparam-name[iParamCount] _srvparam-value[iParamCount] /* _SrvParam-Is-Modifiable[iParamCount] */.
            DOWN.
    END.
END.

PROMON: 

promon <dbname> > R&D > 1. Status Displays > 20. Broker Startup Parameters

The startup parameters for each Login Broker are listed:
 

​​​​​​Status: Broker Startup Parameters
Broker: 0 Pid: 3560 Logins: 4 Pend: 0 Connected: 0
                                                 TCP/IP Version (-ipver): IPV4
                                Maximum Port for Auto Servers (-maxport): 5000
                                Minimum Port for Auto Servers (-minport): 3000
                                Database server side join support (-ssj): Enabled
                              Threaded database server (-threadedServer): Enabled
  Thread stack size for threaded database servers (-threadedServerStack): 2048Kb
                              Maximum Number of Clients Per Server (-Ma): 3
                                        Minimum Clients Per Server (-Mi): 2
                                               Message Buffer Size (-Mm): 8192
                                              Servers per Protocol (-Mp): 0
                                       Maximum Servers Per Broker (-Mpb): 12
                                                       Network Type (-N): TCP
                      Pending client connection time-out (-PendConnTime): 15
                                                       Service Name (-S): 9898
                               Broker server group support (-ServerType): 4GL
                               SQL Server Max Open Cursors (-SQLCursors): 50
Number of seconds for a SQL client to wait for a lock conflict to be resolved (-SQLLockWaitTimeout): 5.
                                  SQL rowid identifier (-SQLQuotedRowid): Standard
                                       SQL Server Stack Size (-SQLStack): 1000
                         SQL Server Statement Cache Size (-SQLStmtCache): 100
     Size [1K byte units] of SQL Server temp table buffer (-SQLTempBuff): 1000
Size [1K byte units] of SQL Server temp table disk storage (-SQLTempDisk): 500000
Size [1K byte units] of SQL Server temp table data page (-SQLTempPageSize): 8
                       Authorized data truncation (-SQLTruncateTooLarge): OFF
                          SQL Autonomous Schema Update (-SQLWidthUpdate): OFF
                          
Broker: 1 Pid: 8888 Logins: 2 Pend: 0 Connected: 0
                                                 TCP/IP Version (-ipver): IPV4
                                Maximum Port for Auto Servers (-maxport): 35000
                                Minimum Port for Auto Servers (-minport): 35005
                                Database server side join support (-ssj): Not Enabled
                              Threaded database server (-threadedServer): Not Enabled
  Thread stack size for threaded database servers (-threadedServerStack): 512Kb
                              Maximum Number of Clients Per Server (-Ma): 2
                                        Minimum Clients Per Server (-Mi): 1
                                               Message Buffer Size (-Mm): 8192
                                              Servers per Protocol (-Mp): 0
                                       Maximum Servers Per Broker (-Mpb): 20
                                                       Network Type (-N): TCP
                      Pending client connection time-out (-PendConnTime): 60
                                                       Service Name (-S): 9898
                               Broker server group support (-ServerType): SQL
                               SQL Server Max Open Cursors (-SQLCursors): 128
Number of seconds for a SQL client to wait for a lock conflict to be resolved (-SQLLockWaitTimeout): 5.
                                  SQL rowid identifier (-SQLQuotedRowid): Standard
                                       SQL Server Stack Size (-SQLStack): 2048
                         SQL Server Statement Cache Size (-SQLStmtCache): 64
     Size [1K byte units] of SQL Server temp table buffer (-SQLTempBuff): 2048
Size [1K byte units] of SQL Server temp table disk storage (-SQLTempDisk): 500000
Size [1K byte units] of SQL Server temp table data page (-SQLTempPageSize): 8
                       Authorized data truncation (-SQLTruncateTooLarge): ON
                          SQL Autonomous Schema Update (-SQLWidthUpdate): ON

If the Primary Broker, is not started with networking, iow no Service (-S) parameter is provided, there are no Server parameters for PROMON to show. The next screen will show the secondary login broker's Server Parameters as depicted below. Information for the Primary Broker can otherwise be found with:

​​​​​Status: Broker Startup Parameters
Broker: 0 Pid: 3560 Logins: 4 Pend: 0 Connected: 0
*** There are no client/server parameters for the primary broker. ***
Enter <return> for more, R, P, T, or X (? for help): 
Broker: 1 Pid: 8888 Logins: 2 Pend: 0 Connected: 0
                                                 TCP/IP Version (-ipver): IPV4
                                Maximum Port for Auto Servers (-maxport): 8910
                                Minimum Port for Auto Servers (-minport): 8901
                              Maximum Number of Clients Per Server (-Ma): 4
                                        Minimum Clients Per Server (-Mi): 2
                                               Message Buffer Size (-Mm): 16384
                                              Servers per Protocol (-Mp): 0
                                       Maximum Servers Per Broker (-Mpb): 2
                                                       Network Type (-N): TCP
                    Pending client connection timeout (-PendConnTimeout): 10
                                                       Service Name (-S): 4041
                               Broker server group support (-ServerType): ABL
...

Database lg file:

At the time of writing, all Secondary Login Broker startup parameters are not listed in the database lg file only those for the Primary Broker. If the Primary Broker, is not started with networking, iow no Service (-S) parameter is provided, there are no Server parameters to use. A zero value will be reported because this is a (networking) Server parameter: