Ever wanted to add an item in the drop down menu on the header or
customize the sections of the user preferences? Here's one way.

So it seems ServiceNow is built on jelly, and if you know the names of the
macros and ui pages you can overwrite them. So I was able to find the name
of the macro. How? That's a day for another post. I'll just go over the
concourse_user_menu today. In the image on top, I pasted the code.

So you want to add something to it. Make a UI Macro called concourse_user_menu
with the following xml. I added a link to DuckDuckGo. But you can see how
this works.

concourse_user_menu

<?xml version="1.0" encoding="utf-8" ?>
<j:jelly
trim="false"
xmlns:j="jelly:core"
xmlns:g="glide"
xmlns:j2="null"
xmlns:g2="glide">

<div class="dropdown pull-left" role="application">
<button id="user_info_dropdown" data-toggle="dropdown"
aria-haspopup="true" aria-expanded="false"
title="${gs.getMessage('User menu')}"
aria-label="${gs.getMessage('User menu')}"
>

<div>
<sn-user-avatar
class="sn-avatar_xs"
aria-hidden="true"
disable-popover="true"
profile="{avatar: '$[gs.getUser().getAvatar()]', initials: '$[gs.getUser().getInitials()]', userID: '$[gs.getUserID()]'}"
enable-presence="true" />

<span class="user-name hidden-xs hidden-sm hidden-md">
$[HTML,NG:gs.getUser().getDisplayName()]
</span>
<span class="sr-only">
${gs.getMessage('User menu')}
</span>
<elevate-role-indicator/>
<span class="caret"/>
</div>
</button>
<ul class="dropdown-menu"
aria-labelledby="user_info_dropdown">

<li role="presentation">
<a href="sys_user.do?sys_id=${gs.getUserID()}&amp;sysparm_view=ess"
target="gsft_main" role="listitem" tabindex="-1" >

${gs.getMessage('Profile')}
</a>
</li>

<j:if test="${gs.getProperty('glide.ui.impersonate_button.enable')}">
<j2:if test="$[new GlideImpersonate().canImpersonate(gs.getUserID())]">
<li role="presentation">
<a href="javascript:void(0)" id="glide_ui_impersonator" sn-modal-show="impersonate" role="listitem" tabindex="-1">
${gs.getMessage('Impersonate User')}
</a>
</li>
</j2:if>
</j:if>

<g2:evaluate var="jvar_elevated_privileges" expression="gs.getSession().getAvailableElevatedRoles()" />
<j2:if test="${!empty(jvar_elevated_privileges)}">
<li role="presentation">
<a href="javascript:void(0)" sn-modal-show="elevateRoles" role="listitem" tabindex="-1">
${gs.getMessage('Elevate Roles')}
</a>
</li>
</j2:if>

<j2:if test="$[gs.getUser().getPreference('user.can.logout') == 'true']">
<li role="presentation">
<a href="logout.do" role="listitem" tabindex="-1">
${gs.getMessage('Logout')}
</a>
</li>
</j2:if>
<li role="presentation">
<a href="https://ddg.gg" role="listitem">
Welcome to the #duckside
</a>
</li>
</ul>
</div>
</j:jelly>