Heading

Tier: native
Surfaces: pagesidebarwidget
Fallback: native
State: settled

Six levels, written the plain Markdown way: # through ######.

# Heading one

## What it holds<!--sb align="center"-->

### Heading three

Canonical form is ATX at every level — a setext heading (Title over =====) is read and becomes # on the next save.

A line break inside a heading has two spellings, because the two forms hold different things. An h1 or h2 carrying a break takes the setext form, which holds one. An h3–h6 is one line by construction, so its break rides a 
 character reference in both directions: ### h1
h2.

align (left | center | right) rides the trailing comment on the heading's own line. A heading always has a line of its own, so a heading whose words are deleted keeps its alignment — ##  is written and read back as an empty centred heading.

A contents block names a page's headings and stores nothing about them.