Although they are drag and drop layouts, the content in HubSpot Blog templates is pretty much coded because of its complexity (various views, authors, topics, pagination, etc).
There is usually a Blog Content module that contains the two main views of the blog: post page and listing page.
Our Act2 Blog II is a bit different. The module shown above is empty and we moved the code in separate sections and modules, for a better understading and the posibility to make small tweaks or add a class or two to the various sections and elements, but please be extra careful when making changes.
If you break anything in your template you can always roll back to a previous version.