I’m merging this, but IMO it would still be nice to have consistency between both styles of blocks, so perhaps you could create a PR for that as well?

Thank you!

I find the no-numbers version more friendly and use it in my blog, exclusively. Those two being different can be seen as a feature: Authors get to choose between a light, friendly version without line numbers for shorter things, fewer distractions, and a serious version with full width, a frame and numbers that you can refer to in the text after. Why take that choice away?

Because if you do have the “choice”, you might end up having both styles in one post, which looks inconsistent. If someone wants the lighter style, they could modify CSS to their will.