Use localized plugin name and description even when the plugin is disabled

Hello Dolly is a specific edge case, it does not translate itself. Rather it’s considered a part of the WordPress codebase, and has a translated title in the WP core language files.

Instead, to have a plugin name translated, you need a language file that maps to the textdomain specified in your plugin, that contains your plugin name. This needs to be in the wp-content/languages/plugins folder or in the appropriate location inside your plugin. e.g. for mytestplugin it could be mytestplugin/mytextdomain-en_US.mo where mytextdomain is what you specified in your plugins header.

This is done via _get_plugin_data_markup_translate ( which has a special override for hello dolly ), and uses load_plugin_textdomain.