configdirectory is rendered as the Configs folder in the theme editor. It includes a
settings_schema.jsonfile and a
settings_data.jsonfile. It will also contain any presets that you choose tho load into your theme such as
layoutdirectory is rendered as the Layouts folder in the theme editor. It contains theme layout templates, which by default is the theme.liquid file. All Liquid templates inside the templates folder are rendered inside the
sectionsdirectory is rendered as the Sections folder in the theme editor. It contains a theme's sections, which are reusable modules of content that can be customized and or re-ordered by users of the theme.
snippetsdirectory is rendered as the Snippets folder in the theme editor. It contains all the theme's Liquid snippet files, which are bits of code that can be referenced in other templates of a theme.
templatesdirectory is rendered as the Templates folder in the theme editor. It contains all other Liquid templates that the theme gives you access to. You can see a detailed list of templates and what properties they give you access to here.