Remove redundant breadcrumb region from page.html.twig

#2 patch apply successfully. I have attached the some after and before attachment.

Correct me if I am wrong but shouldn't we maintain the breadcrumb region so that we stay true to form for the default page.html.twig api documentation etc.

Docs

Yes/no. This really could go either way.

The current code that's in page.html.twig is because of the 7.x -> 8.x port.

In 7.x, breadcrumbs were added as a variable in template_process_page().

This is the code that was converted and why it currently exists in page.html.twig. It's also why you see {{ breadcrumb }} and not {{ page.breadcrumb }} (which would be a region).

In 8.x, after the theme process layer was removed, breadcrumbs were converted into a block after issues arose around its move to the preprocess layer. This is where a "dedicated region" for breadcrumbs was added as well.

Why it got its own region is actually quite unclear (my guess is because some people think they need regions for everything).

Breadcrumbs is now a block (kind of like its own mini-region) and wrapping it in even more region specific markup is completely unnecessary; especially in Bootstrap.

This block can be easily placed anywhere in any of the existing existing regions (as it is doing now in the header region).

As one who adamantly opposes tons of "specific regions" (think Omega), I'm in agreement that this should probably just be removed from page.html.twig.

Also, this is really just a [cleanup] task, not a bug. It doesn't actually do anything or adversely affect any code/logic.