I use an application that I cannot control. It has a preview feature where it launches Word to show contents of files. The application doesn’t use file extensions or MIME types but programmatically is launching MS Word to show the files.
Is there a way to proxy those calls to Libre Office?
I am pretty sure that it can’t. I had this issue over Excel/Calc with SAPB1 but there was an AutoOpen.xls file that was called to open Excel and pass the data to Excel. I managed to rewrite the macro in AutoOpen.xls to call another sheet, .ods this time, with a macro to pass the data to OpenOffice Calc. Eventually, a better solution appeared on the SAP forum but it might not be relevant to your situation as it also relies on there being the AutoOpen spreadsheet to call the appropriate program.
File associations to programs are controlled by the operating system, or you can set it in the operating system.
Here is an example for Windows 10:
Alternatively you can open LibreOffice and open the file from within LibreOffice.
I hope it helps you.
Thanks for the response. The OS does launch Libre Office just fine with the file associations, I can dbl click a docx or odt file and LO opens with no issue. This software programmatically tries to open MS Office apps, rather than handing off to the operating system, so this is the behavior I am trying to intercept.