Update design documentation

wiki/src/contribute/design/installation_assistant.mdwn

@@ -21,13 +21,12 @@ being usable by expert users.
 
 The following scenarios are proposed:
 
-  - [[Install from another Tails (for PC)|install/win/clone-overview]]
-  - [[Install from another Tails (for Mac)|install/mac/clone-overview]]
+  - [[Clone from another Tails (for PC)|install/win/clone-overview]]
+  - [[Clone from another Tails (for Mac)|install/mac/clone-overview]]
   - [[Install from Windows|install/win/usb-overview]]
-  - [[Install from Debian, Ubuntu, or Mint|install/debian/usb-overview]]
+  - [[Install from macOS|install/mac/usb-overview]]
+  - [[Install from Linux (all distributions)|install/linux/usb-overview]]
   - [[Install from Debian, Ubuntu, or Mint using the command line and GnuPG|install/expert/usb-overview]]
-  - [[Install from other Linux distributions|install/linux/usb-overview]]
-  - [[Install from macOS and the command line|install/mac/usb-overview]]
   - [[Burn a DVD|install/dvd]]
   - [[Download only for USB sticks|install/download]]
   - [[Download only for DVDs and virtual machines|install/download-iso]]
@@ -71,8 +70,7 @@ massive amount of content in ikiwiki.
 The [inline directive](https://ikiwiki.info/ikiwiki/directive/inline/) of
 ikiwiki allows embedding a file into another file to avoid duplicating content.
 It is quite limited and brittle, especially when used together with the PO
-plugin. See [[!tails_ticket 6907]]. Many inlines also slow down the build
-process quite a lot.
+plugin. See [[!tails_ticket 6907]].
 
 ### Conditional CSS content
 
@@ -82,7 +80,7 @@ program used to install an intermediary Tails on Windows and Linux we
 wrote:
 
 <pre>
-&lt;span class="windows"&gt;a program called Universal USB Installer.&lt;/span&gt;
+&lt;span class="windows"&gt;a program called Etcher.&lt;/span&gt;
 &lt;span class="linux"&gt;a program called GNOME Disks.&lt;/span&gt;
 </pre>
 
@@ -92,25 +90,20 @@ scenario and elements with the
 
 - Classes for elements potentially displayed on different pages:
   - `clone` for content involving cloning
+  - `download` for all download pages
   - `usb` for content with a USB stick as destination device
-  - `windows` for content for Windows
-  - `mac` for content for macOS
-  - `debian` for content for Debian, Ubuntu, or Mint
-  - `expert` for content for Debian, Ubuntu, or Mint on the command line
-  - `linux` for content for other Linux
   - `upgrade` for content for manual upgrade
 - Classes for elements displayed only on one scenario:
+  - `windows` for [[/install/win/usb|/install/win/usb]]
+  - `mac` for [[/install/mac/usb|/install/mac/usb]]
+  - `linux` for [[/install/linux/usb|/install/linux/usb]]
+  - `expert` for [[/install/expert/usb|/install/expert/usb]]
   - `dvd` for [[/install/dvd-download|/install/dvd-download]]
-  - `vm` for [[/doc/advanced_topics/virtualization|/doc/advanced_topics/virtualization]]
+  - `vm` for [[/install/vm-download|/install/vm-download]]
   - `download-only-img` for [[/install/download|/install/download]]
   - `download-only-iso` for [[/install/download|/install/download-iso]]
   - `install-clone` for [[/install/clone|/install/clone]]
-  - `windows-usb` for [[/install/win/usb|/install/win/usb]]
-  - `mac-usb` for [[/install/mac/usb|/install/mac/usb]]
   - `mac-clone` for [[/install/mac/clone|/install/mac/clone]]
-  - `debian-usb` for [[/install/debian/usb|/install/debian/usb]]
-  - `expert-usb` for [[/install/expert/usb|/install/expert/usb]]
-  - `linux-usb` for [[/install/linux/usb|/install/linux/usb]]
   - `upgrade-clone` for [[/upgrade/clone|/upgrade/clone]]
   - `upgrade-tails` for [[/upgrade/tails|/upgrade/tails]]
 
@@ -124,8 +117,7 @@ installation scenario to follow. It is divided by operating systems:
 
   - Windows
   - macOS
-  - Linux with `APT` and `tails-installer`: Debian, Ubuntu, or Mint
-  - Other Linux distributions
+  - Linux
 
 Notes:
 
@@ -180,9 +172,9 @@ The *overview* is a single page summarizing graphically:
     next and how complex it is. This is particularly important as the
     *steps* are a single and very long page.
 
-For example, the content of the overview for installing from Debian is
-stored in [[!tails_gitweb wiki/src/install/debian/usb-overview.html]] which includes a common block of
-HTML stored in [[!tails_gitweb wiki/src/install/inc/overview.html]] and uses the `debian` CSS
+For example, the content of the overview for installing from Windows is
+stored in [[!tails_gitweb wiki/src/install/win/usb-overview.html]] which includes a common block of
+HTML stored in [[!tails_gitweb wiki/src/install/inc/overview.html]] and uses the `windows` CSS
 class to adapt to the scenario.
 
 <a id="download"></a>
@@ -191,7 +183,7 @@ Download
 ========
 
 The download of the ISO image comes as a dedicated page between the
-overview and steps (except for `clone`, `upgrade-clone`, and `expert`). It
+overview and steps (except for `install-clone`, `mac-clone`, `upgrade-clone`, and `expert`). It
 is also available as a [[standalone page|install/download]].
 
 The download is split as a dedicated page (while still labeled as "Step
@@ -199,6 +191,10 @@ The download is split as a dedicated page (while still labeled as "Step
 possible to skip the download or even the verification but the link to
 do so is labeled as a warning.
 
+Depending on the installation scenario, the download page points to the
+download of the ISO image (on `dvd` and `vm`) or the USB image (on all
+other scenarios).
+
 We propose two download techniques displayed in equal weight and combined
 with two verification techniques that have a level of verification at least as
 good as HTTPS: