As the following pictures suggest, Roblox Studio displays the weight as “Black” while the actual FontWeight is “Heavy”.
Studio:
In code:
The text labels FontFace property still display “Black” as the weight on studio but if I run print(textlabel.FontFace) I get the following result which indicates “Heavy”.
23:50:04.097 Font { Family = rbxasset://fonts/families/SourceSansPro.json, Weight = Heavy, Style = Normal } - Server - Script:1
This might not be an actual bug but it feels weird that the naming isn’t consistent.