Doc: Update info about Extensions mode

- Update the instructions for installing plugins
- Use the instructions for installing plugins also for
  installing extensions
- Describe seraching and sorting extensions, as well as
  opening the preferences

Task-number: QTCREATORBUG-31510
Change-Id: I8f5d770f28bebc8925f6d2338c7c78704291a444
Reviewed-by: hjk <hjk@qt.io>

doc/qtcreator/src/howto/creator-only/creator-how-to-install-extensions.qdoc

@@ -1,6 +1,30 @@
 // Copyright (C) 2024 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only
 
+/*!
+    \page creator-how-to-manage-extensions.html
+    \previouspage creator-how-tos.html
+
+    \ingroup creator-how-to-use
+
+    \title Manage extensions
+
+    In the experimental \uicontrol Extensions mode, you can install extensions
+    from the computer or the web, as well as load and unload them.
+
+    \image qtcreator-extension-mode.webp {Extensions mode}
+
+    To find extensions, start typing in \uicontrol Search.
+
+    You can sort extensions according to their name, vendor, popularity, or
+    update date.
+
+    To set preferences for loading extension from the web or to install
+    extensions, select \inlineimage icons/settings.png.
+
+    \sa {Enable and disable plugins}, {Install extensions}, {Load extensions}
+*/
+
 /*!
     \page creator-how-to-load-extensions.html
     \previouspage creator-how-tos.html
@@ -19,6 +43,7 @@
             \image qtcreator-extension-mode.webp {Extensions mode}
         \li Select an extension.
         \li Select \uicontrol {Load on start}.
+        \li Select \uicontrol {Restart Now} to restart \QC and load the plugin.
     \endlist
 
     \section1 Load extensions from the web
@@ -29,11 +54,56 @@
     To load extensions from the web:
 
     \list 1
-        \li Go to \preferences > \uicontrol Environment > \uicontrol Extensions.
+        \li Go to \preferences > \uicontrol Extensions.
             \image qtcreator-preferences-extensions.webp {Extensions in Preferences}
         \li Select \uicontrol {Use external repository}.
-        \li Select \uicontrol OK.
+        \li In \uicontrol {Server URL} enter the URL of the external repository.
+        \li Select \uicontrol {OK}.
     \endlist
 
-    \sa {Enable and disable plugins}, {Install plugins}
+    \sa {Install extensions}, {Manage extensions}
+*/
+
+/*!
+    \page creator-how-to-install-extensions.html
+    \previouspage creator-how-tos.html
+
+    \ingroup creator-how-to-use
+
+    \title Install extensions
+
+    To install extensions to \QC:
+
+    \list 1
+        \li Go to \preferences > \uicontrol Extensions.
+            \image qtcreator-preferences-extensions.webp {Extensions in Preferences}
+        \li Select \uicontrol {Install Extension}.
+        \include creator-how-to-install-plugins.qdoc install-plugins
+    \endlist
+
+    \section1 Security considerations
+
+    \QC does not check extensions from external vendors for security flaws or
+    malicious intent, so be careful when installing them, as it might leave your
+    computer vulnerable to attacks such as hacking, malware, and phishing.
+
+    Before you install an extension from an external vendor:
+
+    \list
+        \li Check that the extension is compatible with your \QC version and
+            other extensions that you install. You can find this information in
+            the description of the extension in the \uicontrol Extensions mode.
+        \li Check what other users are saying about the extension and how they
+            rate it.
+        \li Make sure the vendor is reputable and known for creating high-quality
+            extensions.
+        \li Check that the extension package was recently updated. Outdated
+            extensions present a bigger risk.
+        \li Check that the extension has good documentation and other means of
+            support.
+        \li Check that the extension mostly has features that you need.
+            All extensions that are loaded on start make \QC start a bit slower.
+    \endlist
+
+    \sa {Load extensions}, {Manage extensions}
 */

doc/qtcreator/src/howto/creator-only/creator-how-to-install-plugins.qdoc

@@ -22,20 +22,25 @@
     To install plugins:
 
     \list 1
-        \li Go to \uicontrol {About Plugins} > \uicontrol {Install Plugins}.
+        \li Go to \uicontrol {About Plugins} > \uicontrol {Install Plugin}.
+//! [install-plugins]
         \li In the \uicontrol Source dialog, enter the path to the archive
             or library that has the plugin.
-            \image qtcreator-install-plugin-source.png
+            \image qtcreator-install-plugin-source.webp {Source dialog}
+        \li In the \uicontrol {Accept Terms and Connections} dialog, select
+            \uicontrol {I accept terms and conditions}.
+            \image qtcreator-install-plugin-accept-terms-and-conditions.webp {Accept Terms and Connections dialog}
         \li In the \uicontrol {Install Location} dialog, select
             \uicontrol {User plugins} to make the plugin available for the
             current user in all compatible \QC instances or
             \uicontrol {\QC installation} to make the plugin available for
             all users of a particular \QC instance.
-            \image qtcreator-install-plugin-location.png
+            \image qtcreator-install-plugin-location.webp {Install Location dialog}
         \li In the \uicontrol Summary dialog, select \uicontrol Finish to
             install the plugin.
-            \image qtcreator-install-plugin-summary.png
+            \image qtcreator-install-plugin-summary.png {Summary dialog}
         \li Select \uicontrol {Restart Now} to restart \QC and load the plugin.
+//! [install-plugins]
     \endlist
 
     \sa {Enable and disable plugins}, {Installation}, {Get and Install Qt}

doc/qtcreator/src/overview/creator-only/creator-configuring.qdoc

@@ -24,7 +24,7 @@
 
     To make \QC behave more like your favorite code editor or IDE, change the
     preferences for generic highlighting, code snippets, and version control
-    systems. Manage plugins to turn on and off \QC features.
+    systems. Manage plugins and extensions to turn on and off \QC features.
 
     To make \QC more accessible, use keyboard navigation or adjust colors and
     zoom levels.
@@ -95,7 +95,7 @@
     For more information about the supported functions, see
     \l{Version Control Systems}.
 
-    \section1 Managing Plugins
+    \section1 Managing Plugins and Extensions
 
     \QC comes with a set of plugins, some of which are disabled by default.
     You can \l{Enable and disable plugins}{enable} disabled plugins if you
@@ -111,6 +111,8 @@
     To install plugins, go to \uicontrol Help > \uicontrol {About Plugins} and
     select \uicontrol {Install Plugins}.
 
+    You can also install and load extensions in the \uicontrol Extensions mode.
+
     \section1 Accessibility
 
     You can use keyboard shortcuts to navigate the UI without a mouse, or set