Heading
Headings get style “Heading 1”, “Heading 2” and “Heading 3” respectively. No changes were made to its defaults.

Subheading
Chapter numbering was enabled via Tools > Chapter numbering (older versions Tools > Outline numbering). It uses type 1,2,3 on all levels. For subheadings show 2 levels is set, for sub-sub-headings show 1 level is set and ( as separator before and ) as separator after.

Subheading
TOC is set up to use “Outline”.

Sub-Subheading
Dummy text

Sub-Subheading
Dummy Text

Heading
Dummy Test