I’m not sure why, but currently only the alignment of canvas panel slots are gettable. Having UPanelSlot provide a function that can be overridden by all child classes (e.g. UBorderSlot) to return HorizontalAlignment, VerticalAlignment and their fill type (whichever exists for the child class) would be great.
I created a system that wraps all buttons with borders at runtime, but I was unable to replicate the existing set alignment on the panel slots once I replaced each button with a border.