diff --git a/data/web/corefork.telegram.org/api/web-events.html b/data/web/corefork.telegram.org/api/web-events.html
index 1fb1e53694..a7611e2975 100644
--- a/data/web/corefork.telegram.org/api/web-events.html
+++ b/data/web/corefork.telegram.org/api/web-events.html
@@ -140,9 +140,15 @@ The GamingCommunication and bot web app libraries by default will use <code>'*'<
 <p>Event data: a JSON object with a string <code>path_full</code> field, containing the path+query component of a <a href="/api/links">t.me deep link</a>.  </p>
 <p>Used to open a <a href="/api/links">t.me deep link</a>. The Web App will be closed.</p>
 <h4><a class="anchor" href="#web-app-setup-back-button" id="web-app-setup-back-button" name="web-app-setup-back-button"><i class="anchor-icon"></i></a><code>web_app_setup_back_button</code></h4>
+<p>Event data: a JSON object with an <code>is_visible</code> boolean field.</p>
+<p>Determines whether to show or hide the back button.  </p>
 <h4><a class="anchor" href="#web-app-open-invoice" id="web-app-open-invoice" name="web-app-open-invoice"><i class="anchor-icon"></i></a><code>web_app_open_invoice</code></h4>
 <h4><a class="anchor" href="#web-app-expand" id="web-app-expand" name="web-app-expand"><i class="anchor-icon"></i></a><code>web_app_expand</code></h4>
+<p>No event payload.</p>
+<p>Expands the web app to the maximum available height.</p>
 <h4><a class="anchor" href="#web-app-request-viewport" id="web-app-request-viewport" name="web-app-request-viewport"><i class="anchor-icon"></i></a><code>web_app_request_viewport</code></h4>
+<p>No event payload.</p>
+<p>Used by web apps to request information about the viewport, clients should call <code>window.Telegram.WebView.receiveEvent("viewport_changed", {})</code></p>
 <h4><a class="anchor" href="#web-app-request-theme" id="web-app-request-theme" name="web-app-request-theme"><i class="anchor-icon"></i></a><code>web_app_request_theme</code></h4>
 <h4><a class="anchor" href="#web-app-ready" id="web-app-ready" name="web-app-ready"><i class="anchor-icon"></i></a><code>web_app_ready</code></h4>
 <h4><a class="anchor" href="#web-app-setup-main-button" id="web-app-setup-main-button" name="web-app-setup-main-button"><i class="anchor-icon"></i></a><code>web_app_setup_main_button</code></h4>