Check
A heading tree that describes the page
A heading tree that describes the page is check B3 in the fifteen-point audit. One h1, a hierarchy that does not skip levels, and headings that label sections rather than decorate them.
What counts as evidence
The heading outline we extracted, with the level of each heading.
How to fix it
Use h2 for sections and h3 for sub-sections; never pick a level for its font size.
Where this sits
B is the group: accessibility, comprehension, or extractability. The groups run in order — a crawler that cannot reach the page never reaches the reading checks — so fix the earliest failing group first. The full definition of all fifteen items is in the standard.