Use this approach to modify the Registry so that other file types are previewable as though they are text files.
Approach found here: http://superuser.com/questions/91804/windows-7-preview-other-file-types-as-text-in-preview-pane
Open the registry editor (regedit in the start menu search) and navigate to computer\HKEY_CLASSES_ROOT\.FILE_EXT, where FILE_EXT is the extension you want to add, such as .twb or .tps or .tds or .sql
Make 2 new string values (REG_SZ) under the file extension's key, Content Type andPerceivedType
(note, only the PerceivedType is needed if Content Type already exists -- also note that PerceivedType has no spaces)
Set the value of Content Type to text/plain and PerceivedType to text
For other Tableau items, like twbx, tdsx that are zip folders, add a PerceivedType as compressed in order for Windows File Explorer to provide insight into those files