Improved description, support for "unlisted" via DFRN as well.

mod/settings.php

@@ -840,7 +840,7 @@ function settings_content(App $a)
 	]);
 
 	$unlisted = Renderer::replaceMacros($opt_tpl, [
-		'$field' => ['unlisted', DI::l10n()->t('Should public posts be unlisted?'), DI::pConfig()->get(local_user(), 'system', 'unlisted'), DI::l10n()->t('Your public posts will not appear on the community page or in search results, nor will they be transported to relay servers.')],
+		'$field' => ['unlisted', DI::l10n()->t('Should public posts be unlisted?'), DI::pConfig()->get(local_user(), 'system', 'unlisted'), DI::l10n()->t('Your public posts will not appear on the community page or in search results, nor will they be transported to relay servers. However they can appear on public feeds from other servers.')],
 	]);
 
 	$blockwall = Renderer::replaceMacros($opt_tpl, [

src/Protocol/DFRN.php

@@ -1052,6 +1052,7 @@ class DFRN
 		if ($item['private']) {
 			// Friendica versions prior to 2020.3 can't handle "unlisted" properly. So we can only transmit public and private
 			XML::addElement($doc, $entry, "dfrn:private", ($item['private'] == Item::PRIVATE ? Item::PRIVATE : Item::PUBLIC));
+			XML::addElement($doc, $entry, "dfrn:unlisted", $item['private'] == Item::UNLISTED);
 		}
 
 		if ($item['extid']) {
@@ -2405,6 +2406,11 @@ class DFRN
 
 		$item["private"] = XML::getFirstNodeValue($xpath, "dfrn:private/text()", $entry);
 
+		$unlisted = XML::getFirstNodeValue($xpath, "dfrn:unlisted/text()", $entry);
+		if (!empty($unlisted) && ($item['private'] != Item::PRIVATE)) {
+			$item['private'] = Item::UNLISTED;
+		}
+
 		$item["extid"] = XML::getFirstNodeValue($xpath, "dfrn:extid/text()", $entry);
 
 		if (XML::getFirstNodeValue($xpath, "dfrn:bookmark/text()", $entry) == "true") {