Fidelity is a CGNS-based format and descriptions of these solver attributes can be found on the CGNS page. Note that it is recommended to set the Use Family Conditions attribute to False when exporting to the Fidelity format.
Note: The Fidelity solver expects boundary and volume condition data to be written in legacy mode (i.e. not using Family nodes). Therefore, it is recommended to set Use Family Conditions to False when exporting for the Fidelity format.