Proper Pluralization

Hi @elliotcondon

I just wanted to flag that the use of '1' in plural i18n functions like _n() shouldn't be used and instead the placeholder is more appropriate. This is mostly due to Arabic, Russian and other multi-plural languages as often the singular doesn't indicate 1 (in Arabic it's 0, and in Russian it's 1, 21, 31, etc)

From the Plugin Handbook;
"singular – the singular form of the string (note that it can be used for numbers other than one in some languages, so '%s item' should be used instead of 'One item')"
https://developer.wordpress.org/plugins/internationalization/how-to-internationalize-your-plugin/#plurals

Example of this on translate.wp.org for your plugin;
Arabic - https://translate.wordpress.org/projects/wp-plugins/advanced-custom-fields/stable/ar/default/?filters%5Boriginal_id%5D=7728762
Russian - https://translate.wordpress.org/projects/wp-plugins/advanced-custom-fields/stable/ru/default/?filters%5Boriginal_id%5D=7728762

A couple of instances I see in the github repo for the plugin;
https://github.com/AdvancedCustomFields/acf/blob/20a0aaa6a8f40e62ca0bc35ebae07415ca8bcfde/includes/admin/tools/class-acf-admin-tool-import.php#L138
https://github.com/AdvancedCustomFields/acf/blob/f7061f75ddd36b3b11c11083596ac8125be2e5dd/includes/admin/tools/class-acf-admin-tool-export.php#L174
*These following ones don't use 1 explicitly but they don't provide the %s placeholder.
https://github.com/AdvancedCustomFields/acf/blob/20a0aaa6a8f40e62ca0bc35ebae07415ca8bcfde/includes/admin/admin-field-groups.php#L156
https://github.com/AdvancedCustomFields/acf/blob/20a0aaa6a8f40e62ca0bc35ebae07415ca8bcfde/includes/admin/admin-field-groups.php#L243

Also note while looking through the plugin I found the acf._n JS function here;
https://github.com/AdvancedCustomFields/acf/blob/482b8284a54df284d5bd84cb95ed3cc6ce2df763/assets/js/acf-input.js#L644
*This function switches singular/plural depending if the number == 1 which doesn't support languages like Arabic/Russian.

All the best,
Cheers

Start with includes/admin/tools/class-acf-admin-tool-import.php, includes/admin/tools/class-acf-admin-tool-export.php, and the two locations in includes/admin/admin-field-groups.php cited in the issue. Then inspect acf._n in assets/js/acf-input.js; review the listed pluralization calls and verify that PHP and JavaScript handling supports placeholders and the plural rules described for Arabic and Russian.