SQL 2005 has introduced a new system database referred as Resource database, namely RDB. Its mdf file name is ‘mssqlsystemresource.mdf’. Resource database is a read-only database that contains all the system objects that are included with SQL Server 2005. All system objects such as sys.objects are physically stored in the Resource database, but they logically appear in the sys schema of every database.
You can run
SELECT [name], object_definition(object_id) from sys.system_objects
from any database, which will give a same output.