<!--
- Copyright 2016 Soren Stoutner <soren@stoutner.com>.
+ Copyright © 2016-2020,2022 Soren Stoutner <soren@stoutner.com>.
- This file is part of Privacy Browser <https://www.stoutner.com/privacy-browser>.
+ This file is part of Privacy Browser Android <https://www.stoutner.com/privacy-browser-android>.
- Privacy Browser is free software: you can redistribute it and/or modify
+ Privacy Browser Android is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
- Privacy Browser is distributed in the hope that it will be useful,
+ Privacy Browser Android is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
- along with Privacy Browser. If not, see <http://www.gnu.org/licenses/>. -->
+ along with Privacy Browser Android. If not, see <http://www.gnu.org/licenses/>. -->
<html>
-<head>
-<!-- We have to make an image into its own block to center it. -->
-<style>
- h3 {
- color: 0D4781;
- }
-
- img.center {
- display: block;
- margin-left: auto;
- margin-right: auto;
- }
-</style>
-</head>
-
-<body>
-<h3>Browser Identification</h3>
-
-<p>When web browsers connect to websites, they send a user agent, which identifies the browser and the
- rendering capabilities it possesses. They website can use this information to decide which version of the
- website to send to the browser. For example, many websites have different versions for desktop and
- mobile browsers.</p>
-
-<p>By default, Privacy Browser uses the built-in user agent that comes with the WebView installed on the
- device. You can see what it is by going to the <strong>Settings</strong> screen and setting the <strong>User
- agent</strong> to <strong>WebView Default</strong>. The screenshot below shows a Nexus 6P running Android 6.0.1
- with Android System WebView 51.0.2704.81 installed.</p>
-
-<img class="center" src="images/user_agent.png" height="640" width="360">
-
-<p>There is enough information in the user agent that sometimes only a few visitors to a website will be the same. If the user agent
- is combined with another piece of non-unique identifying information, often it results in a unique fingerprint.
- The Electronic Frontier Foundation created a tool called <a href="https://panopticlick.eff.org/">Panopticlick</a>
- to demonstrate how much information can be gleaned from these sources. If this test is run with JavaScript enabled the
- amount of information that is disclosed increases greatly. <a href="https://www.browserleaks.com">Browser Leaks</a> and
- <a href="https://amiunique.org/">Am I Unique</a> are also good sources of information.</p>
-
-<img class="center" src="images/panopticlick.png" height=640" width="360">
-
-<p>Privacy Browser allows you to change the user agent. There are several preset options that match common browsers and operating systems.
- Privacy Browser also has its own user agent, which is simply PrivacyBrowser/1.0. For tracking purposes, anything that is rare is easier
- to track. If Privacy Browser becomes common and many people use PrivacyBrowser/1.0 as their user agent, it will be a good choice for privacy.
- For now, choosing something that has lots of hits on a web server, like <strong>Edge 13 on Windows 10</strong>, allows the device to
- blend in with the crowd. Firefox or Chrome provide less privacy because they auto-update and their version numbers change so quickly
- that it is likely the user agents included in Privacy Browser will often be out of step with the majority of user agents in the
- server logs.</p>
-
-<p>A second reason to change the user agent is to convince the web server to send the desktop version of the web page, which often works
- better on modern smart phones than the mobile version. For this purpose, PrivacyBrowser/1.0 works well, because web servers typically
- default to the desktop version unless they recognize a phone browser agent.</p>
-
-<p>Android's WebView does not allow the user agent to be blank. If it is, WebView simply sends the default user-agent to the server.</p>
-</body>
+ <head>
+ <meta charset="UTF-8">
+
+ <link rel="stylesheet" href="../css/theme.css">
+
+ <!-- Setting the color scheme instructs the WebView to respect `prefers-color-scheme` @media CSS. -->
+ <meta name="color-scheme" content="light dark">
+ </head>
+
+ <body>
+ <h3><svg class="header"><use href="../shared_images/devices_other.svg#icon"/></svg> Browser Identification</h3>
+
+ <p>When web browsers connect to websites, they send a user agent, which identifies the browser and the rendering capabilities it possesses.
+ The web server can use this information to decide which version of the website to send to the browser.
+ For example, many websites have different versions for desktop and mobile browsers.</p>
+
+ <p>By default, Privacy Browser uses its own user agent, which is <code>PrivacyBrowser/1.0</code>. This sends a minimum of information to the web server.
+ Because web servers do not recognize this to be a mobile user agent, they typically display the desktop version of the site.</p>
+
+ <p>By comparison, WebView’s default user agent divulges a large amount of information about the hardware and software of the device.
+ On the <strong>Settings</strong> screen, selecting <strong>WebView Default</strong> as the <strong>User agent</strong> displays the user agent that will be sent.
+ The screenshot below shows a Pixel 2 XL running Android 10 with Android System WebView 84.0.4147.125 installed.
+ Most web servers will recognize this as a mobile browser and will display the mobile version of the site if they have one.</p>
+
+ <img class="center" src="images/user_agent.png">
+
+ <p>There is enough information in the user agent that sometimes only a few visitors to a website will be the same.
+ If the user agent is combined with another piece of non-unique identifying information, often it results in a unique fingerprint.
+ The Electronic Frontier Foundation created a tool called <a href="https://panopticlick.eff.org/">Panopticlick</a> to demonstrate how much information can be gleaned from these sources.
+ If this test is run with JavaScript enabled the amount of information that is disclosed increases greatly.
+ <a href="https://www.browserleaks.com">Browser Leaks</a> and <a href="https://amiunique.org/">Am I Unique</a> are also good sources of information on this topic.</p>
+
+ <img class="center" src="../shared_images/panopticlick.png">
+
+ <p>There are several preset user agents that match common browsers and operating systems. For browser fingerprinting purposes, anything that is rare is easier to track.
+ If Privacy Browser becomes common and many people use <code>PrivacyBrowser/1.0</code> as their user agent, it will be a good choice for privacy.
+ Firefox or Chrome are the most common user agents, but they auto-update and their version numbers change so quickly that it is likely the user agents included in Privacy Browser
+ will often be out of step with the majority of user agents in the server logs.</p>
+
+ <p>Some websites <a href="https://www.stoutner.com/user-agent-problems/">do not function correctly</a> if they do not recognize the user agent.
+ Using domain settings to set the user agent to <strong>WebView Default</strong>, or another user agent that is commonly recognized, usually resolves the problem.
+ Android’s WebView does not allow the user agent to be blank. If it is, WebView simply sends the default user agent to the server.</p>
+ </body>
</html>
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