Feature: ask permission before loading structured data

src/UI/Comparison/ComparisonTool.svelte

@@ -29,7 +29,11 @@
   export let feature: Feature
   export let readonly = false
   export let sourceUrl: Store<string>
-
+  /**
+   * A switch that signals that the information should be downloaded.
+   * The actual 'download' code is _not_ implemented here
+   */
+  export let downloadInformation : UIEventSource<boolean>
   export let collapsed: boolean
   const t = Translations.t.external
 
@@ -49,8 +53,14 @@
 <LoginToggle {state} silentFail>
   {#if !$sourceUrl || !$enableLogin}
     <!-- empty block -->
+    {:else if !$downloadInformation}
+    <button on:click={() => downloadInformation.set(true)}>
+      Attempt to download information from the website {$sourceUrl}
+    </button>
   {:else if $externalData === undefined}
-    <Loading />
+    <div class="flex justify-center">
+      <Loading />
+    </div>
   {:else if $externalData["error"] !== undefined}
     <div class="subtle low-interaction rounded p-2 px-4 italic">
       <Tr t={Translations.t.external.error} />