This patch make Xfce use "gnome" as the default icon theme and enable font antialias.

Taken from ArchLinux.

diff -upr xfce4-settings-4.12.0.orig/xfsettingsd/xsettings.xml xfce4-settings-4.12.0/xfsettingsd/xsettings.xml
--- xfce4-settings-4.12.0.orig/xfsettingsd/xsettings.xml	2015-02-24 03:33:11.000000000 +0200
+++ xfce4-settings-4.12.0/xfsettingsd/xsettings.xml	2015-03-01 09:52:24.376869688 +0200
@@ -6,8 +6,8 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <channel name="xsettings" version="1.0">
   <property name="Net" type="empty">
     <property name="ThemeName" type="empty"/>
-    <property name="IconThemeName" type="empty"/>
+    <property name="IconThemeName" type="string" value="gnome"/>
     <property name="DoubleClickTime" type="int" value="400"/>
     <property name="DoubleClickDistance" type="int" value="5"/>
     <property name="DndDragThreshold" type="int" value="8"/>
@@ -19,9 +19,9 @@
   </property>
   <property name="Xft" type="empty">
     <property name="DPI" type="empty"/>
-    <property name="Antialias" type="int" value="-1"/>
+    <property name="Antialias" type="int" value="1"/>
     <property name="Hinting" type="int" value="-1"/>
-    <property name="HintStyle" type="string" value="hintnone"/>
+    <property name="HintStyle" type="string" value="hintfull"/>
     <property name="RGBA" type="string" value="none"/>
     <!-- <property name="Lcdfilter" type="string" value="none"/> -->
   </property>
ix/diff/po/doc/guix-manual.es.po?id=4a226e547f2a6576b871bfac2a35d8a737cf1aa6'>diff</a></td><td class='form'><form class='right' method='get' action='/guix/log/po/doc/guix-manual.es.po'>
<input type='hidden' name='id' value='4a226e547f2a6576b871bfac2a35d8a737cf1aa6'/><select name='qt'>
<option value='grep'>log msg</option>
<option value='author'>author</option>
<option value='committer'>committer</option>
<option value='range'>range</option>
</select>
<input class='txt' type='search' size='10' name='q' value=''/>
<input type='submit' value='search'/>
</form>
</td></tr></table>
<div class='path'>path: <a href='/guix/log/?id=4a226e547f2a6576b871bfac2a35d8a737cf1aa6'>root</a>/<a href='/guix/log/po?id=4a226e547f2a6576b871bfac2a35d8a737cf1aa6'>po</a>/<a href='/guix/log/po/doc?id=4a226e547f2a6576b871bfac2a35d8a737cf1aa6'>doc</a>/<a href='/guix/log/po/doc/guix-manual.es.po?id=4a226e547f2a6576b871bfac2a35d8a737cf1aa6'>guix-manual.es.po</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/guix/log/po/doc/guix-manual.es.po?id=4a226e547f2a6576b871bfac2a35d8a737cf1aa6&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2020-10-27 00:40:24 +0100'>2020-10-27</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=b35550c3d8ab5db3210319269ef5ad1dd271a43a'>nls: Update.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-10-16 15:00:49 +0200'>2020-10-16</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=4dd989708c7ab34df0b60ce9b6c0a8ca5c15e858'>nls: Update manual translations.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-04-12 00:18:05 +0200'>2020-04-12</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=935ef44b398353b5b6af94e185d7b0c3d833db0b'>nls: Update.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-03-23 00:06:58 +0100'>2020-03-23</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=86603d8660e42a3b5d8b407e456a98429943bc7e'>nls: Update.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2020-02-14 09:01:29 +0000'>2020-02-14</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=57718bdf6823aef291d114a457c42c984ac42791'>Revert "nls: Update 'es' translation of the manual."</a><span class='msg-avail'>...</span></td><td>Christopher Baines</td></tr>
<tr><td><span title='2020-02-14 04:45:53 +0100'>2020-02-14</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=d156e3fbcd6fc61a39d1d32622b90b0f8f741729'>nls: Update 'es' translation of the manual.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2019-08-31 21:29:46 +0200'>2019-08-31</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=b212fef4b076faccdd36335c728fd71321778716'>nls: Update 'es' translation of the manual.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2019-05-13 10:57:11 +0200'>2019-05-13</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=8548cf6e95917f7b56042d2d275a08e91eedf31a'>nls: Update es translation.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-05-01 11:33:32 +0200'>2019-05-01</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=a3b32d57d6677fded92dbd3f4ecafbf9aceeb855'>nls: Fix cross-reference syntax error in 'guix-manual.es.po'.</a><span class='msg-avail'>...</span></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-05-01 10:16:58 +0200'>2019-05-01</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=d3619b296fd1db6441e09bb51b55a4264b9fd0ed'>nls: Update manual translations for de, es, fr, and zh_CN.</a></td><td>Ludovic Courtès</td></tr>
<tr><td><span title='2019-04-25 18:55:12 +0200'>2019-04-25</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=57e2b24dc03e44e4e379436e63d29231f1f9d28c'>nls: Update 'es' translation.</a></td><td>Julien Lepiller</td></tr>
<tr><td><span title='2019-04-23 23:56:16 +0200'>2019-04-23</span></td><td><a href='/guix/commit/po/doc/guix-manual.es.po?id=6227e1b7477b71f31ea3bf8a74c32fe7238dcece'>doc: Add Spanish translation.</a><span class='msg-avail'>...</span></td><td>Miguel Ángel Arruga Vivas</td></tr>