If you right-click on a book in the Books folder, you can select Update from Original Source. Sometimes I forget where I originally added the book from. Could you find a way to display the source path? I know I can look it up in the appDef file, but that isn’t very user-friendly. You could add another column to the right in the books list (so that it would normally not be visible, but could be scrolled to) that gives the source path. Or you could add a confirmation dialog when you select Update from Original Source that says “Update this book from C:\path\to\file?” (But if the source file hasn’t changed, you would probably just get the “No files were updated” message, and still wouldn’t know the path - which isn’t ideal…)
The information is in the .appdef file if you don’t mind reading a XML file.
Its path is /app-definition/books/book/source
Most people would be coming from Paratext projects so the location is usually predictable and or familiar. It is more people who are working on multiple projects like you and me who will need this.
Adding it in the table would be convenient. Or having a popup from a right click menu that told you the path.
Actually, I was really thinking about this feature being helpful more with Reading App Builder, where the source file location isn’t predictable. But I put the request here for SAB because I was doing other SAB stuff and wasn’t thinking… 
There is a RAB page like this. https://community.software.sil.org/c/rab
In those cases it is much more likely the path could be forgotten.
Yes, but I know that if the feature is added to SAB, we get it in RAB for free as well… 
In SAB 4.7, to see the original source path, right click on a book in the books table and select ‘Show Original Source’. The path will be displayed in a message box.
Thanks for that, Richard!