AppendableData ! Again !
History repeats itself: Structured Data -> Appendable data -> Mutable Data -> Appendable Data
So, you are going to define the 4th version of this kind of data. This is typically over-engineering. In French there is an expression to describe a situation like this: the better is the enemy of the good.
At least, you can take advantage of if to put back signatures in the new structure. I have mentioned several times that this was a regression compared to initial SD, without them:
- no multi-sig
- no static check