Steps to reproduce the issue

Enable language debugging in Joomla 4 and create yourself a menu item pointing to Search.

Visit the menu item

NOTE the lack of translated placeholder text

Expected result

Well here is where it gets complex.

The debug toolbar says that MOD_FINDER_SEARCH_VALUE is untranslated

So you go down the rabbit hole looking for MOD_FINDER_SEARCH_VALUE and you find its used as

Text::script('MOD_FINDER_SEARCH_VALUE', true);

However once the value is added to JS its not actually then used as the place holder of the input field for the search

So the fix is

• wanting to actually use the JS language string somewhere, then we need a

Factory::getLanguage()->load('mod_finder');

in the com_finder - tmpl/search/default.php before Text::script('MOD_FINDER_SEARCH_VALUE', true);

• Then we ALSO NEED some javascript (beyond me!) to populate this translated string as a placeholder of the input box (like the search MODULE does correctly)

Actual result

 "joomla.jtext": {
            "MOD_FINDER_SEARCH_VALUE": "??MOD_FINDER_SEARCH_VALUE??",
            "JSHOWPASSWORD": "**Show Password**",
            "JHIDEPASSWORD": "**Hide Password**"
        },

System information (as much as possible)

Safari on Mac

Additional comments

Compare with the search MODULE which has a placeholder: