What does N'[Uncategorized (Local)] mean?
The @name parameter is a parameter of msdb.dbo.sp_add_category and not EXEC.

See the sp_add_category documentation:


  [ @name = ] 'name'
  
  The name of the category to be added. The name must be unique within the specified class. name is sysname, with no default.


[Uncategorized (Local)] just indicates a default category when you didn't specify a category on the SQL Agent Job. The leading N just indicates the string is nvarchar and not varchar.

Please read through Organize Jobs to learn more about job categories

The code you are looking at is most likely just a scripted out job. For example when I right-click a random job on the SQL Server I'm looking at and script job as &gt; create &gt; new query editor window this is the result:

IF NOT EXISTS (SELECT name FROM msdb.dbo.syscategories WHERE name=N'[Uncategorized (Local)]' AND category_class=1)
BEGIN
EXEC @ReturnCode = msdb.dbo.sp_add_category @class=N'JOB', @type=N'LOCAL', @name=N'[Uncategorized (Local)]'
IF (@@ERROR &lt;&gt; 0 OR @ReturnCode &lt;&gt; 0) GOTO QuitWithRollback

END

DECLARE @jobId BINARY(16)
EXEC @ReturnCode =  msdb.dbo.sp_add_job @job_name=N'Warmup_SSRS_EP', 
        @enabled=1, 
        @notify_level_eventlog=0, 
        @notify_level_email=3, 
        @notify_level_netsend=0, 
        @notify_level_page=0, 
        @delete_level=0, 
        @description=N'Warmup_SSRS_EP', 
        @category_name=N'[Uncategorized (Local)]', 
        @owner_login_name=N'domain\user', 
        @notify_email_operator_name=N'monitor operator', @job_id = @jobId OUTPUT


Where the creation of the category is just included in the script to make sure it exists because otherwise the following procedures would error out.