by Matthew Adams Windows & Software Expert ODT is the file format for OpenOffice and LibreOffice Writer documents.

When an ODT document is corrupted, an error message might pop up stating The file .odt is corrupt and therefore cannot be opened. Consequently, users can’t usually open corrupted ODT files by clicking on File > Open. […]
https://officerambo.com/how-to-recover-and-fix-corrupted-odt-files/