A DWT file is an AutoCAD drawing template file that is used as a starter for creating drawings that can be saved as DWG files. Such template files provide initial settings such as unit types, the precision required, title blocks, layer names, line types, and other similar information for lateral conversion to proper drawing files. Both AutoCAD and CoreCAD can be used to read the template files and utilize them further.
XLSX is well-known format for Microsoft Excel documents that was introduced by Microsoft with the release of Microsoft Office 2007. Based on structure organized according to the Open Packaging Conventions as outlined in Part 2 of the OOXML standard ECMA-376, the new format is a zip package that contains a number of XML files. The underlying structure and files can be examined by simply unzipping the .xlsx file.
You can also convert DWT into many other file formats. Please see the complete list below.