Headings
SC 2.4.6 - What does "Headings and Labels" mean?
You open a page and the first heading is “Overview”. Overview of what? You scroll and find “Details”, “More information” and “Other”. Not one of them tells you what is in the section. You have to read everything to find out what the page is about.
SC 1.3.1 - What does "Info and Relationships" mean?
You can see that a line is a heading because it is big and bold. You can see that three lines belong together because they each start with a bullet. You can see which column a number belongs to because it sits underneath the word “Price”. None of that is visible to a screen reader. It only knows what the code says. Success criterion 1.3.1 is the rule that closes that gap: the structure a sighted visitor perceives must also be available in the markup.