When you use the command dbexport, a folder is created with database files and with a schema named database_name.sql in it.
If you look at that file, the tables normally as a perfix like "name_of_user".name_of_table which if you modify the "name_of_user" that with be the owner of the table when import the database.
Attention when you modify the .sql file because if you do something that you shouldn't you will never be able to import that database again.
If you import the database as Informix, this user will become the owner.
I presume that you want to see the owner Informix when you consult the databases into the dbspaces.
When you look into the sysmaster database of the instance, there is an table called sysdatabases that have the information about the databases that exists on the instance and the respective owner.