This is difference between the default preference of Firefox 34.0 beta 3 and one of 33.0.

Default pref Javascript files (Firefox 33.0 for Linux x86_64):
(omni.ja){/greprefs.js,/defaults/pref/services-sync.js}, (browser/omni.ja)/defaults/preferences/{firefox.js,firefox-branding.js,firefox-l10n.js}, (webapprt/omni.ja)/defaults/preferences/prefs.js
Default pref Javascript files (Firefox 34.0 beta 3 for Linux x86_64):
(omni.ja){/greprefs.js,/defaults/pref/services-sync.js}, (browser/omni.ja)/defaults/preferences/{firefox.js,firefox-branding.js,firefox-l10n.js}, (webapprt/omni.ja)/defaults/preferences/prefs.js
PrefFirefox 33.0Firefox 34.0 beta 3
apz.allow_checkerboardingundefinedtrue
apz.asyncscroll.throttleundefined100
apz.asyncscroll.timeoutundefined300
apz.content_response_timeoutundefined300
apz.cross_slide.enabledundefinedfalse
apz.danger_zone_xundefined50
apz.danger_zone_yundefined100
apz.enlarge_displayport_when_clippedundefinedfalse
apz.fling_accel_base_multundefined1.0
apz.fling_accel_interval_msundefined500
apz.fling_accel_supplemental_multundefined1.0
apz.fling_frictionundefined0.002
apz.fling_repaint_intervalundefined75
apz.fling_stop_on_tap_thresholdundefined0.05
apz.fling_stopped_thresholdundefined0.01
apz.max_velocity_inches_per_msundefined-1.0
apz.max_velocity_queue_sizeundefined5
apz.min_skate_speedundefined1.0
apz.num_paint_duration_samplesundefined3
apz.overscroll.enabledundefinedfalse
apz.overscroll.fling_frictionundefined0.02
apz.overscroll.fling_stopped_thresholdundefined0.4
apz.overscroll.min_pan_distance_ratioundefined1.0
apz.overscroll.snap_back.massundefined1000.0
apz.overscroll.snap_back.spring_frictionundefined0.1
apz.overscroll.snap_back.spring_stiffnessundefined0.6
apz.overscroll.stretch_factorundefined0.5
apz.pan_repaint_intervalundefined250
apz.touch_start_toleranceundefined0.2222222
apz.use_paint_durationundefinedtrue
apz.velocity_biasundefined1.0
apz.velocity_relevance_time_msundefined150
apz.x_skate_size_multiplierundefined1.5
apz.x_stationary_size_multiplierundefined3.0
apz.y_skate_size_multiplierundefined2.5
apz.y_stationary_size_multiplierundefined3.5
apz.zoom_animation_duration_msundefined250
browser.newtabpage.directory.sourcehttps://tiles.services.mozilla.com/v2/links/fetchhttps://tiles.services.mozilla.com/v2/links/fetch/%LOCALE%
browser.safebrowsing.appRepURLundefinedhttps://sb-ssl.google.com/safebrowsing/clientreport/download?key=%GOOGLE_API_KEY%
browser.safebrowsing.downloads.enabledundefinedtrue
browser.safebrowsing.downloads.remote.enabledundefinedfalse
datareporting.healthreport.service.providerCategorieshealthreport-js-provider-defaulthealthreport-js-provider-default,healthreport-js-provider-beta
datareporting.policy.dataSubmissionPolicyAcceptedfalseundefined
datareporting.policy.dataSubmissionPolicyAcceptedVersionundefined0
datareporting.policy.dataSubmissionPolicyBypassAcceptancefalseundefined
datareporting.policy.dataSubmissionPolicyBypassNotificationundefinedfalse
datareporting.policy.dataSubmissionPolicyResponseTime0undefined
datareporting.policy.dataSubmissionPolicyResponseTypeundefined
devtools.command-button-frames.enabledundefinedfalse
devtools.remote.wifi.visibleundefinedfalse
devtools.storage.enabledundefinedfalse
devtools.styleeditor.transitionsundefinedtrue
devtools.toolbox.splitconsoleEnabledundefinedfalse
devtools.toolbox.splitconsoleHeightundefined100
devtools.webide.enabledfalsetrue
dom.fetch.enabledundefinedfalse
dom.global-constructor.disable.mozContacttrueundefined
dom.navigator-property.disable.mozContactstrueundefined
dom.sms.maxReadAheadEntriesundefined0
dom.udpsocket.enabledundefinedfalse
dom.webcrypto.enabledfalsetrue
experiments.manifest.cert.checkAttributesfalseundefined
experiments.manifest.cert.requireBuiltinfalseundefined
experiments.manifest.certs.1.commonName*.cdn.mozilla.netundefined
experiments.manifest.certs.1.issuerNameCN=Cybertrust Public SureServer SV CA,O=Cybertrust Incundefined
font.default.trserifundefined
font.default.x-balticserifundefined
font.default.x-central-euroserifundefined
font.minimum-size.tr0undefined
font.minimum-size.x-baltic0undefined
font.minimum-size.x-central-euro0undefined
font.name.monospace.trmonospaceundefined
font.name.monospace.x-balticmonospaceundefined
font.name.monospace.x-central-euromonospaceundefined
font.name.sans-serif.trsans-serifundefined
font.name.sans-serif.x-balticsans-serifundefined
font.name.sans-serif.x-central-eurosans-serifundefined
font.name.serif.trserifundefined
font.name.serif.x-balticserifundefined
font.name.serif.x-central-euroserifundefined
font.size.fixed.tr12undefined
font.size.fixed.x-baltic12undefined
font.size.fixed.x-central-euro12undefined
font.size.variable.tr16undefined
font.size.variable.x-baltic16undefined
font.size.variable.x-central-euro16undefined
layers.scroll-graphfalseundefined
layers.tiled-drawtarget.enabledundefinedfalse
layout.async-containerless-scrolling.enabledundefinedtrue
layout.css.font-features.enabledfalseundefined
layout.css.prefixes.font-featuresundefinedtrue
layout.css.ruby.enabledundefinedfalse
layout.css.scroll-behavior.damping-ratioundefined1.0
layout.css.scroll-behavior.enabledundefinedfalse
layout.css.scroll-behavior.spring-constantundefined250.0
layout.spammy_warnings.enabledundefinedtrue
lightweightThemes.getMoreURLundefinedhttps://addons.mozilla.org/%LOCALE%/firefox/themes
lightweightThemes.recommendedThemesundefined[{"id":"recommended-1","homepageURL":"https://addons.mozilla.org/firefox/addon/a-web-browser-renaissance/","headerURL":"resource:///chrome/browser/content/browser/defaultthemes/1.header.jpg","footerURL":"resource:///chrome/browser/content/browser/defaultthemes/1.footer.jpg","textcolor":"#000000","accentcolor":"#f2d9b1","iconURL":"resource:///chrome/browser/content/browser/defaultthemes/1.icon.jpg","previewURL":"resource:///chrome/browser/content/browser/defaultthemes/1.preview.jpg","author":"Sean.Martell","version":"0"},{"id":"recommended-2","homepageURL":"https://addons.mozilla.org/firefox/addon/space-fantasy/","headerURL":"resource:///chrome/browser/content/browser/defaultthemes/2.header.jpg","footerURL":"resource:///chrome/browser/content/browser/defaultthemes/2.footer.jpg","textcolor":"#ffffff","accentcolor":"#d9d9d9","iconURL":"resource:///chrome/browser/content/browser/defaultthemes/2.icon.jpg","previewURL":"resource:///chrome/browser/content/browser/defaultthemes/2.preview.jpg","author":"fx5800p","version":"1.0"},{"id":"recommended-3","homepageURL":"https://addons.mozilla.org/firefox/addon/linen-light/","headerURL":"resource:///chrome/browser/content/browser/defaultthemes/3.header.png","footerURL":"resource:///chrome/browser/content/browser/defaultthemes/3.footer.png","textcolor":"#None","accentcolor":"#ada8a8","iconURL":"resource:///chrome/browser/content/browser/defaultthemes/3.icon.png","previewURL":"resource:///chrome/browser/content/browser/defaultthemes/3.preview.png","author":"DVemer","version":"1.0"},{"id":"recommended-4","homepageURL":"https://addons.mozilla.org/firefox/addon/pastel-gradient/","headerURL":"resource:///chrome/browser/content/browser/defaultthemes/4.header.png","footerURL":"resource:///chrome/browser/content/browser/defaultthemes/4.footer.png","textcolor":"#000000","accentcolor":"#000000","iconURL":"resource:///chrome/browser/content/browser/defaultthemes/4.icon.png","previewURL":"resource:///chrome/browser/content/browser/defaultthemes/4.preview.png","author":"darrinhenein","version":"1.0"},{"id":"recommended-5","homepageURL":"https://addons.mozilla.org/firefox/addon/carbon-light/","headerURL":"resource:///chrome/browser/content/browser/defaultthemes/5.header.png","footerURL":"resource:///chrome/browser/content/browser/defaultthemes/5.footer.png","textcolor":"#3b3b3b","accentcolor":"#2e2e2e","iconURL":"resource:///chrome/browser/content/browser/defaultthemes/5.icon.jpg","previewURL":"resource:///chrome/browser/content/browser/defaultthemes/5.preview.jpg","author":"Jaxivo","version":"1.0"}]
loop.CSPundefineddefault-src 'self' about: file: chrome:; img-src 'self' data: http://www.gravatar.com/ about: file: chrome:; font-src 'none'; connect-src wss://*.tokbox.com https://*.opentok.com https://*.tokbox.com wss://*.mozilla.com https://*.mozilla.org wss://*.mozaws.net
loop.debug.dispatcherundefinedfalse
loop.debug.loglevelundefinedError
loop.debug.sdkundefinedfalse
loop.enabledfalsetrue
loop.feedback.baseUrlundefinedhttps://input.mozilla.org/api/v1/feedback
loop.feedback.productundefinedLoop
loop.fxa_oauth.profileundefined
loop.fxa_oauth.tokendataundefined
loop.legal.ToS_urlundefinedhttps://accounts.firefox.com/legal/terms
loop.legal.privacy_urlundefinedhttps://www.mozilla.org/privacy/
loop.oauth.google.redirect_uriundefinedurn:ietf:wg:oauth:2.0:oob:auto
loop.oauth.google.scopeundefinedhttps://www.google.com/m8/feeds
loop.soft_start_hostnameundefinedsoft-start.loop.services.mozilla.com
loop.soft_start_ticket_numberundefined-1
loop.throttledundefinedtrue
media.getusermedia.screensharing.allow_on_old_platformsundefinedfalse
media.play-stand-aloneundefinedtrue
network.http.spdy.enabled.http2draftfalsetrue
privacy.clearOnShutdown.openWindowsundefinedfalse
privacy.cpd.openWindowsundefinedfalse
privacy.panicButton.enabledundefinedtrue
privacy.panicButton.enabledLocalesundefinedast da de en-GB en-US es-AR es-CL es-ES es-MX fi fr fy-NL he hu it ja ja-JP-mac ko lv nb-NO nn-NO pa-IN pl pt-BR rm ru sk sl zh-TW
privacy.panicButton.useLocaleListundefinedfalse
security.apps.privileged.CSP.defaultundefineddefault-src *; script-src 'self'; object-src 'none'; style-src 'self' 'unsafe-inline'
security.csp.newbackend.enabletrueundefined
security.ssl.enable_alpnfalsetrue
security.tls.version.fallback-limitundefined1
security.tls.version.min01
services.sync.prefs.sync.browser.search.selectedEnginetrueundefined
ui.scrollToClick0undefined
webgl.disable-angleundefinedfalse
webgl.prefer-native-glfalseundefined