class="o1-section" data-o1-section="main"
Section files help organize files into groups. For example, a 2-column layout would need to store the elements in the left column separately from the elements of the right column. Section files are used to achieve this grouping.
This markup is used to map a DOM node to a section file on the filesystem. When a file is dropped into such a DOM node, it will be routed into the corresponding section file on the filesystem.
To identify the section file on the filesystem, Boomla will look for the
closest DOM node that is marked as file (via the o1-file class). That file
identifies the parent of the section file.
The value of the data-o1-section attribute is then used to select the section
file by its name (within its parent file as explained above).
Note that when no ancestor exists that fulfills this contract, the entire document (page) will be recognized as the drop target, specified by the path in the location bar.