We don't use holder anywhere besides .heading-holder. Most other containers, wrappers, boxes or holders are named
container.
Let's unify the naming here by
CodeSearch for .heading-holder: https://codesearch-beta.wmcloud.org/search/?q=heading-holder&files=&excludeFiles=&repos=
This would be the block (at best) –– it's neither element nor modifier currently. But that's not my main concern.
We would separate core and other skins more without a clear naming architecture. If everything else is banner-container, cnotice-logo-container, cnotice-message-container`, read-more-container it's not logically otherwise.
Setting to declined, as it would need quite some work and we have to re-focus on other priorities with start of the new Readers Experience team.