for the first time, i'm digging around in the docs for how to
properly license various types of recipes, so a couple simple
questions to start with, at least so i can make a first pass of
cleaning up some content in front of me.

as we established recently, packagegroup files need no licensing,
the obvious observation being that they represent the collection of
licenses that comprise them. however, i notice that the
packagegroup.bbclass file does indeed define a default license:

LICENSE ?= "MIT"

so not only does a packagegroup have a default (MIT) license, but it's
conditional suggesting one could give it a different license. what
other licenses would make sense for a packagegroup? I'm sticking with
the default that packagegroup recipe files need no LICENSE assignment,
but now i'm curious as to what other options there are (or perhaps
that that default assignment in packagegroup.bbclass is obsolete).

the same sort of question can be asked about image files, including
the generic OE core-image*.bb recipe files. of all those current
core-image files:

core-image-base.bb
core-image-minimal.bb
core-image-minimal-dev.bb
core-image-minimal-initramfs.bb
core-image-minimal-mtdutils.bb
core-image-tiny-initramfs.bb

fail into two camps.

the first sets a license, then inherits core-image:

LICENSE = "MIT"
inherit core-image

the second type simply "require"s one of the other recipe files so it
has no need to set its own license, as in core-image-minimal-dev.bb:

require core-image-minimal.bb

similar to packagegroups, does a core-image recipe really need a
separate LICENSE setting, or could that be added to core-image.bbclass
to centralize it (if it's even needed at all)?

finally, WRT .bbappend files, the original recipes will have their
own licenses and if the .bbappend file is doing nothing but adding
some configuration (you know, PACKAGECONFIG, EXTRA_OEMAKE, that sort
of thing), then there should be no need for licensing in the bbappend
file. does all this sound reasonable so far?

rday