So after more research I found that sys.sp_MSrepl_getpublisherinfo lives in a database named mssqlsystemresource, which lives in Sql Server's binn folder. This database is invisible to SSMS, but you can copy and attach it as a different name to have full access. This process is described here:
I have copied that text here, in case that page goes away in the future:
Giving credit where credit is due, I found the following info I am
about to post at the following location:
Since the engine has hooks that hide the mssqlsystemresource database
from users, you don't have direct access to it through the GUI.
However, there is a way around this:
Determine where the system databse files live, and keep this path handy:
SELECT REPLACE(filename, 'master.mdf', '')
WHERE fileid = 1
Stop the SQL Server service;
Copy the files mssqlsystemresource.*df -> resource_copy.*df. NOTE: do not rename or remove the mssqlsystemresource files!
Start the SQL Server service;
Run the following code in a new query window:
'<path from above>resource_copy.mdf',
'<path from above>resource_copy.ldf'
Now, the system will no longer identify this database as a "special" database
- You can easily scan through the names of system objects that might otherwise be unknown (and browse any code associated with these
objects) from a GUI (like SQL Server Management Studio).