--- a/mobile/android/app/mobile.js
+++ b/mobile/android/app/mobile.js
@@ -386,16 +386,19 @@ pref("devtools.debugger.unix-domain-sock
 pref("devtools.remote.usb.enabled", false);
 pref("devtools.remote.wifi.enabled", false);
 
 pref("font.size.inflation.minTwips", 0);
 
 // When true, zooming will be enabled on all sites, even ones that declare user-scalable=no.
 pref("browser.ui.zoom.force-user-scalable", false);
 
+// With the typical screen sizes on mobile devices, we want to wrap page sources by default.
+pref("view_source.wrap_long_lines", true);
+
 // When removing this Nightly flag, also remember to remove the flags surrounding this feature
 // in GeckoPreferences and BrowserApp (see bug 1245930).
 #ifdef NIGHTLY_BUILD
 pref("ui.bookmark.mobilefolder.enabled", true);
 #else
 pref("ui.bookmark.mobilefolder.enabled", false);
 #endif