It looks that odb to odf conversion is related to transformation of two different types of OpenDocument based file types. In this it seems to be export of texts from .odb databases to .odf files that are used for interchange purposes. You can do this in several productivity suites based on the OpenDocument schema.
Convert Apache OpenOffice OpenDocument database to Open Document Interchange Format (ODIF).
We found 2 software records in the database related to .odb to .odf file format conversion.
Microsoft Windows software - convert odb to odf on Windows
Older multi-platform office productivity suite
Convert from odb file format
The tables with software actions are a good pointer for what a certain program does with various file types and often may give users a good hint how to perform certain file conversion, for example the above-mentioned odb to odf. However, it is not perfect and sometimes can show results which are not really usable because of how certain programs work with files and the possible conversion is thus actually not possible at all.
Apple macOS / Mac OS X software - convert odb to odf on OS X
A full-featured set of office applications for Mac OS X