See https://docs.yoctoproject.org/3.1.21/dev-manual/dev-manual-common-tasks.html#setting-up-and-running-a-multiple-configuration-build. For dunfell, this section says: "The location for these multiconfig configuration files is specific. They must reside in the current build directory in a sub-directory of conf named multiconfig." For master, this section says: "The location for these multiconfig configuration files is specific. They must reside in the current Build Directory in a sub-directory of conf named multiconfig or within a layer’s conf directory under a directory named multiconfig." The text for master appears to be correct for dunfell as well. The change to allow multiconfig files to be in layer conf directories was added in 2016 (long before the dunfell release) by the following commits: * https://git.openembedded.org/bitbake/commit/?id=518b9015c2be8d3894277a8e54890d6f04d656c0 * https://git.openembedded.org/openembedded-core/commit/?id=a6a3894fb2cb2097d2404b8b8cb2b85df595cfa9
Submitted a patch to address this: https://lists.yoctoproject.org/g/docs/message/3520
Fixed by this commit: https://git.yoctoproject.org/yocto-docs/commit/?h=dunfell&id=4961ddc9848f6569307107c10ff132532944ccaa