If any kind of gdbtable to adf conversion is possible, it would be export of ArcGIS data between different formats. Such export should be doable with ArcGIS or similar software that supports ArcGIS .gdbtable files, unfortunately we have not found any specific information about this. If you need help with ArcGIS files, it would be perhaps best to contact ESRI support or some community website.
Updated: February 24, 2023