What is the correct naming procedure of text domain, directory and theme name?

Question

This is the example on the WordPress codex:

/*
* Theme Name: My Theme
* Author: Theme Author
* Text Domain: my-theme
* Domain Path: /languages
*/

Is it possible the for the directory be called "mytheme" or does it have to be "my-theme"?

Answer 1

From https://developer.wordpress.org/themes/functionality/internationalization/

Themes that are hosted on WordPress.org the text domain must match the slug of your theme URL (wordpress.org/themes/). This is needed so that the translations from translate.wordpress.org work correctly.

The text domain name must use dashes and not underscores and be lowercase. For example, if the theme’s name My Theme is defined in the style.css or it is contained in a folder called my-theme the text domain should be my-theme.