Installed 8.x.1.3 on a local system for testing. It appears that many of the regions that are listed in your documentation are not-implemented or somehow suppressed. For instance, if I go into the structure/blocks and ask for the block region demo I get Header, Primary Menu, Highlighted, Page Title, Breadcrumb, Left Sidebar, Content, Right Sidebar, three footer container regions. But not the top container or bottom container and several other regions shown on your project page in drupal8-w3css-theme-color-guidance.png
Furthermore, in block layout, if I move my main content into one of the top containers, if doesn't show up on the page at all.
All the regions are listed in your info.yml file but I don't know how to diagnose why they aren't appearing in block preview or available for displaying blocks.
Fixed
1.3
User interface
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It's likely this issue predates Contrib.social: some issue and comment data are missing.