[fpc-pascal] Should data structures part in LCL be moved to FCL?

[Marco van de Voort]

In our previous episode, leledumbo said:
> I found some data structure related units in LCL (AvgLvlTree, DynamicArray,
> DynHashArray, DynQueue, etc.). To be consistent (LCL: visual components,
> FCL: non-visual), wouldn't it be better to move them to FCL?

What is there that is not already in FPC ? Are these not simply leftovers of
older times when Lazarus still had to compile with 1.0.x?