The mqsibrowse command used to exist, but was only ever intended to be used to help IBM support staff in active support cases. It originally dumped the contents of the MQSI database tables (such as BROKERRESOURCES) and then changed to dumping the config store on-disk files, but none of this is used by ACE so the command isn't used anymore.
As far as I know, there isn't any documentation for the command; is there something specific you need?