Documentation for block types?

[HydrogenC]

I failed to find any documentation about the block types (defined in unet_2d_blocks.py) on the official site, is there anywhere to find any docs for them?
What I am trying to figure out is the difference between UpBlock2d and UpDecoderBlock2d (or DownBlock2d and DownDecoderBlock2d). I dived into the code and found them implemented in very similar ways, especially with resnet_time_scale_shift defined to false. So why exactly are their differences?

[yiyixuxu]

cc @DN6
I think we should consolidate if it is indeed the same