[Question]Sortorder?

[Puschpa]

I think about creating some new blocks for my server. In the blocks.xml each block now has a SortOrder1 and SortOrder2 value. Now my question: what these values are for, what is the system behind them, what would happen if a block is lacking them, or have the wrong ones? Thanks in advance

 

[Guppycur]

What we see, and creative menu order, I think.