Some questions about the pymatgen library


first of all thank you for making this project openly available.

I´m just starting to work with the pymatgen library and have some questions:
-the pymatgen.core.periodic_table.Element enum has the attribut X which gives the electronegativity but which electronegativity is that (as far as I know there are at least 4 different types of electronegativity)
-is there a way to get the polarizability with just the periodic_table.Element enum? I can also get the material_id if that is neccessary.
-I used the get_dos_by_material_id of the MPRester class but I´m not so sure what the result is representing. I know its a DOS object and I applyied the get_element_dos function. In the result is then a dict which contains list of values for orbitals. My question is what do these lists represent?
-I used the get_exp_thermo_data of the MPRester class to get the corresponding thermodyn data object of this class but I`m a little bit confused with the documentation of the pymatgen.analysis.thermochemistry module. As far as I understood th function of the MPRester class returns a list of ThermoData objects. My question is what is meant by the data_type attribut (I have some guesses but not for all of the attributes) A, B, C, D, E, F (free energy?), G (gibbs energy?), H (enthalpy?)
-another question about the pymatgen.analysis.thermochemistry module. I didn´t found the possibility to get the heat of atomization and the heat of vaporization. Is it possible to get these values?

thank you in advance for taking your time to answer the questions
best regards