I know modifying the source code is one lof the 7 deadly sins, but I am currently trying to track down an issue with our wishlists not loading the items in sandbox. We just did a refresh and it works fine on prod but not on sandbox. The lists themselves are getting pulled but show "No Items Yet" even though the list in the netsutie backed has items that are on the site. The list was created from the site by my test customer. I was hoping to find the source code for the ProductList.ServiceController to add some log statements to it to see where things are ending up getting missed. Does anyone know where that might be in SCA 2020.2.2? I have looked through the file cabinet and dont see that specific file.

I wouldn't modify files in the filecabinet. You can download the source code as a zipfile from Web Site Hosting Files > Live Hosting Files > SSP Applications > NetSuite Inc. - SCA 202x.x.x > Development > _Sources. I would locate the controller and then extend it in an extension and the relevant methods you want to log and then you can remove those once you find what's going on.

I find downloading the core extremely helpful for reference purposes only.

Did you re-deploy the SSP 2.0 when you created the website in Sandbox?

I did, what this ended up being is we have a new field we added to an ancillary record that requires permissions. I upped the perissions on the ProductList service and everything is good now.