This is a a direct followup to bug #10712. It works more or less the same way: The variable IMAGE_ROOTFS_EXCLUDE_PATH specifies a list of directories relative to the root of the rootfs, and these directories will be excluded from the resulting rootfs image. If an entry ends with a slash, only the contents are omitted, not the directory itself.

The intended use of the variable is to exclude certain directories from the rootfs, and then include said directories in other partitions, using the feature already implemented in #10712.