[RFC] Defining semantics for "implied directories" in the image spec

[neersighted]

opencontainers/image-spec#970 represents an attempt to codify the semantics for "implied directories" (directories which must exist to apply a layer, but that do not have their own tar entries), particularly as it relates to filesystem attributes.

As this affects how high-level runtimes interpret images and is fairly low-level, input and awareness from runtime authors is requested. Thanks!

[thaJeztah]

I'm "+1" on at least codifying it into the spec, to make sure that implementations follow the same conventions on this (otherwise behaviour may differ between them, leading to unexpected results).