add this member is hidden tooltip

frontend/src/lib/components/PartialMemberCard.svelte

@@ -6,7 +6,7 @@
     type User,
     type CustomPreferences,
   } from "$lib/api/entities";
-    import { Icon } from "sveltestrap";
+    import { Icon, Tooltip } from "sveltestrap";
   import FallbackImage from "./FallbackImage.svelte";
 
   export let user: User;
@@ -40,6 +40,8 @@
   };
 
   $: pronouns = getPronouns(member);
+
+  let iconElement: HTMLElement;
 </script>
 
 <div>
@@ -50,7 +52,8 @@
     <a class="text-reset fs-5 text-break" href="/@{user.name}/{member.name}">
       {member.display_name ?? member.name}
       {#if member.unlisted === true}
-        <Icon name="lock"/>
+        <span bind:this={iconElement} tabindex={0}><Icon name="lock"/></span>
+        <Tooltip target={iconElement} placement="top">This member is hidden</Tooltip>
       {/if}
     </a>
     {#if pronouns}