WPML: the wpml-config.xml compatibility file

wpml-config.xml is the declarative way to tell WPML what in your plugin/theme is translatable — custom fields, custom post types, taxonomies, options, and shortcodes. It needs zero runtime code: WPML reads it and configures itself. This is the first (and often only) compatibility step for most plugins. For runtime language logic see wpml-language-api; for dynamic strings see wpml-string-translation.

Where the file goes and when it's read

• Plugin: wp-content/plugins/<your-plugin>/wpml-config.xml (plugin root). Verified discovery at class-wpml-config.php:152,169.
• Theme: child then parent theme root (class-wpml-config.php:262,268).
• WPML re-reads config files in admin only, on a whitelist of pages (plugins.php, themes.php, WPML's own pages, string-translation.php when ST is active), filterable via wpml_config_white_list_pages (class-wpml-config.php:16-41). So after editing the file, visit Plugins or a WPML settings page to make WPML re-parse it — it is not re-read on every front-end request.

Skeleton (illustrative — plugin-specific keys)