Index: wp-admin/includes/plugin-install.php
===================================================================
--- wp-admin/includes/plugin-install.php	(revision 62208)
+++ wp-admin/includes/plugin-install.php	(working copy)
@@ -313,6 +313,13 @@
 function install_search_form( $deprecated = true ) {
 	$type = isset( $_REQUEST['type'] ) ? wp_unslash( $_REQUEST['type'] ) : 'term';
 	$term = isset( $_REQUEST['s'] ) ? urldecode( wp_unslash( $_REQUEST['s'] ) ) : '';
+	$tab  = isset( $_REQUEST['tab'] ) ? urldecode( wp_unslash( $_REQUEST['tab'] ) ) : '';
+
+	// Don't install the search form on the `Favorites` tab.
+	if ( 'favorites' === $tab ) {
+		return;
+	}
+
 	?>
 	<form class="search-form search-plugins" method="get">
 		<input type="hidden" name="tab" value="search" />