What DSN file is MS Access using for ODBC Linked Tables? I set up a linked tables in Microsoft Access to connects to an remote database using ODBC with a File DSN. But which DSN file is Access using now? I want to examine it and compare it with the other versions. 

The Linked Table Manager only lists the tables and the name of the database. 

I tried renaming all of the DSN files I could find, and the ODBC connection still runs. Is Access storing the connection string itself?
IIRC, Access uses either a machine DSN or a file DSN. I only have Access 2016 installed but I don't think this has changed much. There should be an External Data tab in the ribbon, click on ODBC Database. This shows you two tabs: File Data Source and Machine Data Source. 


This image shows the MS Access Database source but I generally see folks create one specific to the Access database they created.

You can also views this by opened the ODBC Data Sources from Administrator tools. There is a 32 and a 64 bit version of this and you may need to check both.

Also, with regards to Access storing the connection itself. It is possible to setup a DSN-less connection using macros. You can see this KB on how that is done to know where to check in your Access database.