Both those strings seem to be located in wp-admin/includes/meta-boxes.php. They don’t have any filters attached to them, so they’re not meant to be (easily) altered by your code.
However, both those strings are internationalized (ie, run through a translation function) to allow WordPress’s interface to be translated into languages other than English. The i18n functions—__() and _e()—both use translate(), which provides a filter, gettext, that you can use to control what is displayed.
Caveats:
- This may adversely affect the translatability of your plugin.
- If WordPress ever changes the strings used in these locations, your filter will no longer work.
With that in mind, this code should be a good starting point.
add_filter( 'gettext', 'wpse406946_change_meta_strings', 10, 3 );
/**
* Change the "Published On:" string and remove the "status: " line from
* my CPT's meta box.
*
* @param string $translation The translated string.
* @param string $text The original string.
* @param string $domain The current text domain.
* @return string The filtered translated text.
*/
function wpse406946_change_meta_strings( $translation, $text, $domain ) {
// Checks for the custom post type.
if ( 'my_post_type' === get_post_type() && 'default' === $domain ) {
// Unhooks the filter to prevent infinite loops.
remove_filter( 'gettext', 'wpse406946_change_meta_strings', 10, 3 );
if ( 'Published on: %s' === $text ) {
$translation = __( 'Created on: $%s', $domain );
}
// The "Status: Published" message is actually 2 parts.
// This should catch both.
if ( 'Status:' === $text || 'Published' === $text ) {
$translation = '';
}
// Rehooks the filter.
add_filter( 'gettext', 'wpse406946_change_meta_strings', 10, 3 );
}
return $translation;
}