The following 3rd parties are integrated into Graph and Chart:

In the folder Chart And Graph/Themes/Common/Fonts :

Each font has it's own folder with full license detials

Exo2 - SIL OPEN FONT LICENSE - https://www.fontsquirrel.com/license/exo-2
ABeeZee - SIL OPEN FONT LICENSE - https://www.fontsquirrel.com/license/abeezee
Comprehension - SIL OPEN FONT LICENSE - https://www.fontsquirrel.com/license/comprehension
Enriqueta - SIL OPEN FONT LICENSE - https://www.fontsquirrel.com/license/enriqueta
Fengardo-neue - SIL OPEN FONT LICENSE - https://www.fontsquirrel.com/license/fengardo-neue
Overpass - SIL OPEN FONT LICENSE - https://www.fontsquirrel.com/license/overpass
Rambla - SIL OPEN FONT LICENSE - https://www.fontsquirrel.com/license/rambla
Scada - SIL OPEN FONT LICENSE - https://www.fontsquirrel.com/license/scada

SimpleJson in the folder Chart And Graph/SimpleJSON-master:
Licensed under MIT license :https://github.com/Bunny83/SimpleJSON/blob/master/LICENSE