I don’t know if Collabora CODE supports odg. The only new part of my suggestion is a configuration (in seahub_settings.py?) and create the “New” list entries depending on the given file types: All of the parts are already implemented and only need to be extended. Find answers to Open Office Calc - Trim first two characters in a cell from the expert community at Experts Exchange. That needs to have the templates for them ready on seafile server, add the entries for the file types in “New” menu the code to transfer the templates on request and of course the translation for the supported languages. My approach is to have support for OpenDocument file types in seafile as well. But that is a second rate solution, just a workaround. A workaround could be to upload template files for OpenDocument file types and copy them on demand. It sticks to that format and all formatting is gone on program exit. Collabora CODE will open it as a text file (regardless of the file extension).

You could try to create an empty file using proper suffix using the new file option.

Templates for openoffice or libreoffice