This is difference between the default preference of Firefox 47.0 beta 1 and one of 45.0.

Preference difference
PrefFirefox 46.0Firefox 47.0 beta 1
alerts.showFaviconsundefinedfalse
apz.displayport_expiry_msundefined15000
apz.fling_repaint_interval16undefined
apz.pan_repaint_interval16undefined
apz.smooth_scroll_repaint_interval16undefined
browser.history.allowPopStatetrueundefined
browser.history.allowPushStatetrueundefined
browser.history.allowReplaceStatetrueundefined
browser.meta_refresh_when_inactive.disabledundefinedfalse
browser.newtabpage.remote.modeundefinedproduction
browser.safebrowsing.blockedURIs.enabledundefinedfalse
browser.safebrowsing.downloads.remote.block_dangerousundefinedtrue
browser.safebrowsing.downloads.remote.block_dangerous_hostundefinedtrue
browser.safebrowsing.downloads.remote.block_potentially_unwantedundefinedfalse
browser.safebrowsing.downloads.remote.block_uncommonundefinedfalse
browser.safebrowsing.provider.mozilla.listsmozstd-track-digest256,mozstd-trackwhite-digest256,mozfull-track-digest256mozstd-track-digest256,mozstd-trackwhite-digest256,mozfull-track-digest256,mozplugin-block-digest256,mozplugin2-block-digest256
browser.search.param.yahoo-frmoz35undefined
browser.search.param.yahoo-fr-jamozffundefined
datareporting.healthreport.about.reportUrlUnifiedhttps://fhr.cdn.mozilla.net/%LOCALE%/v4/undefined
devtools.command-button-noautohide.enabledundefinedfalse
devtools.command-button-tilt.enabledfalseundefined
devtools.devedition.promo.enabledfalsetrue
devtools.fontinspector.enabledtruefalse
devtools.gcli.jquerySrchttps://ajax.googleapis.com/ajax/libs/jquery/2.1.1/jquery.min.jshttps://cdnjs.cloudflare.com/ajax/libs/jquery/2.2.1/jquery.min.js
devtools.gcli.lodashSrchttps://cdnjs.cloudflare.com/ajax/libs/lodash.js/2.4.1/lodash.min.jshttps://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.6.1/lodash.min.js
devtools.gcli.underscoreSrchttps://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.7.0/underscore-min.jshttps://cdnjs.cloudflare.com/ajax/libs/underscore.js/1.8.3/underscore-min.js
devtools.loader.hotreloadundefinedfalse
devtools.markup.collapseAttributesundefinedtrue
devtools.memory.custom-breakdowns{}undefined
devtools.memory.custom-census-displaysundefined{}
devtools.memory.custom-dominator-tree-breakdowns{}undefined
devtools.memory.custom-dominator-tree-displaysundefined{}
devtools.migration.warningsfalsetrue
devtools.performance.ui.enable-jit-optimizationsfalseundefined
devtools.performance.ui.show-jit-optimizationsundefinedfalse
devtools.responsive.html.enabledundefinedfalse
devtools.scratchpad.enabledundefinedfalse
devtools.tilt.enabledtrueundefined
devtools.tilt.intro_transitiontrueundefined
devtools.tilt.outro_transitiontrueundefined
devtools.toolbox.toolbarSpec["splitconsole", "paintflashing toggle","tilt toggle","scratchpad","resize toggle","eyedropper","screenshot --fullpage", "rulers", "measure"]["splitconsole", "paintflashing toggle","scratchpad","resize toggle","eyedropper","screenshot --fullpage", "rulers", "measure"]
devtools.webconsole.autoMultilineundefinedtrue
dom.details_element.enabledundefinedfalse
dom.document.scrollingElement.enabledundefinedfalse
dom.identity.enabledfalseundefined
dom.ipc.cpows.forbid-unsafe-from-browserundefinedtrue
dom.max_child_script_run_time10undefined
dom.mozBrowserFramesEnabledundefinedtrue
dom.permissions.enabledtrueundefined
dom.serviceWorkers.interception.enabledtrueundefined
dom.serviceWorkers.interception.opaque.enabledtrueundefined
dom.vr.poseprediction.enabledundefinedfalse
dom.workers.maxPerDomain2050
gfx.logging.peak-texture-usage.enabledundefinedfalse
gfx.logging.texture-usage.enabledundefinedfalse
gfx.xrender.enabledtruefalse
identity.fxaccounts.settings.urihttps://accounts.firefox.com/settingshttps://accounts.firefox.com/settings?service=sync&context=fx_desktop_v3
image.http.acceptimage/png,image/*;q=0.8,*/*;q=0.5*/*
javascript.options.dump_stack_on_debuggee_would_runundefinedfalse
javascript.options.throw_on_debuggee_would_runundefinedfalse
javascript.options.wasmundefinedfalse
layers.offmainthreadcomposition.testing.enabledfalseundefined
layout.accessiblecaret.allow_script_change_updatesundefinedfalse
layout.accessiblecaret.always_tiltundefinedfalse
layout.accessiblecaret.caret_shown_when_long_tapping_on_empty_contentundefinedfalse
layout.css.text-align-true-value.enabledfalseundefined
layout.css.text-align-unsafe-value.enabledundefinedfalse
media.benchmark.framesundefined300
media.benchmark.timeoutundefined1000
media.benchmark.vp9.thresholdundefined150
media.hardware-video-decoding.force-enabledundefinedfalse
media.wave.decoder.enabledundefinedtrue
narrate.enabledundefinedtrue
narrate.rateundefined0
narrate.testundefinedfalse
narrate.voiceundefinedautomatic
network.cookie.alwaysAcceptSessionCookiesfalseundefined
network.mdns.use_js_fallbackundefinedfalse
plugin.state.libplugins2undefined
plugin.state.npatgpc2undefined
plugin.state.npbispbrowser2undefined
plugin.state.npesteid-firefox-plugin2undefined
plugins.rewrite_youtube_embedsfalsetrue
privacy.sanitize.migrateClearSavedPwdsOnExitfalseundefined
security.ssl3.ecdhe_ecdsa_chacha20_poly1305_sha256undefinedtrue
security.ssl3.ecdhe_rsa_chacha20_poly1305_sha256undefinedtrue
security.view-source.reachable-from-inner-protocolundefinedfalse
security.webauth.u2fundefinedfalse
security.webauth.u2f.softtokenundefinedfalse
security.webauth.u2f.usbtokenundefinedfalse
services.kinto.baseundefinedhttps://firefox.settings.services.mozilla.com/v1
services.kinto.bucketundefinedblocklists
services.kinto.onecrl.checkedundefined0
services.kinto.onecrl.collectionundefinedcertificates
services.sync.enabledtrueundefined
services.sync.prefs.sync.services.sync.syncedTabs.showRemoteIconsundefinedtrue
services.sync.syncedTabs.showRemoteIconsundefinedtrue
services.sync.syncedTabsUIRefreshfalseundefined
toolkit.telemetry.optoutSampletrueundefined
ui.popup.disable_autohideundefinedfalse
urlclassifier.blockedTableundefinedtest-block-simple,mozplugin-block-digest256
urlclassifier.disallow_completionstest-malware-simple,test-phish-simple,test-unwanted-simple,test-track-simple,test-trackwhite-simple,test-forbid-simple,goog-downloadwhite-digest256,mozstd-track-digest256,mozstd-trackwhite-digest256,mozfull-track-digest256test-malware-simple,test-phish-simple,test-unwanted-simple,test-track-simple,test-trackwhite-simple,test-forbid-simple,goog-downloadwhite-digest256,mozstd-track-digest256,mozstd-trackwhite-digest256,mozfull-track-digest256,test-block-simple,mozplugin-block-digest256,mozplugin2-block-digest256
Default pref Javascript files
FileFirefox 46.0Firefox 47.0 beta 1
browser/omni.ja!/defaults/preferences/devtools.jspresentpresent
browser/omni.ja!/defaults/preferences/firefox-branding.jspresentpresent
browser/omni.ja!/defaults/preferences/firefox-l10n.jspresentpresent
browser/omni.ja!/defaults/preferences/firefox.jspresentpresent
browser/omni.ja!/defaults/preferences/webide-prefs.jspresentpresent
omni.ja!/defaults/pref/services-sync.jspresentpresent
omni.ja!/greprefs.jspresentpresent
webapprt/omni.ja!/defaults/preferences/prefs.jspresentpresent