Signals Notebook: Is it possible to upload macro-enabled Excel files

Yes, macro-enabled Excel files can be uploaded in Signals Notebook.

Note:  Macros can only be run in desktop version of Excel and NOT in  Office Online. You can open a workbook that contains macros in Office Online, but you will not see the macros. In Office Online, you can make changes and save the file and the macros will still be there to work with when you open it in Desktop Excel.
 
To enable macros in Desktop Excel, kindly refer to: Signals Notebook - macros in Office files are blocked