are there any actual "container layers" left?

["Robert P. J. Day" <rpjday@crashcourse.ca>]

  perusing the BSP developer's guide:

https://docs.yoctoproject.org/bsp-guide/bsp.html

and early on, there is a reference to "container layers," which i
remember because i recall bringing up the issue of how to refer to OE
layers that were themselves layers while containing even *more* layers
as subdirectories.

  first, since this is the BSP guide, it's a bit weird to use
meta-openembedded as an alleged example of a container layer. but
that's not the issue.

  as i recall, the phrase "container layer" was meant to describe
something which was itself a valid layer, while containing further
valid layers; if memory serves, "meta-intel" used to look like that.
but that's not what it looks like anymore, it's just a regular layer:

  https://git.yoctoproject.org/meta-intel/tree/

as another example, the "meta-xilinx" checkout clearly fetches
numerous layers, but it itself is not a layer, so it doesn't fit the
definition of a "container layer".

  is this terminology still useful? and under what circumstances?

rday