This is difference between the default preference of Firefox 62.0 beta 6 and one of 61.0.1.

Preference difference
PrefFirefox 62.0Firefox 63.0 beta 4
accessibility.typeaheadfind.enabletimeouttrueundefined
accessibility.typeaheadfind.manualundefinedtrue
app.update.enabledtrueundefined
app.update.url.detailshttps://www.mozilla.org/%LOCALE%/firefox/noteshttps://www.mozilla.org/%LOCALE%/firefox/beta/notes
app.update.url.manualhttps://www.mozilla.org/firefox/https://www.mozilla.org/firefox/beta
apz.allow_double_tap_zoomingundefinedtrue
browser.bookmarks.editDialog.showForNewBookmarksundefinedtrue
browser.chrome.faviconstrueundefined
browser.chromeURLchrome://browser/content/undefined
browser.contentHandlers.types.0.titlechrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.0.typeapplication/vnd.mozilla.maybe.feedundefined
browser.contentHandlers.types.0.urichrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.1.titlechrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.1.typeapplication/vnd.mozilla.maybe.feedundefined
browser.contentHandlers.types.1.urichrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.2.titlechrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.2.typeapplication/vnd.mozilla.maybe.feedundefined
browser.contentHandlers.types.2.urichrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.3.titlechrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.3.typeapplication/vnd.mozilla.maybe.feedundefined
browser.contentHandlers.types.3.urichrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.4.titlechrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.4.typeapplication/vnd.mozilla.maybe.feedundefined
browser.contentHandlers.types.4.urichrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.5.titlechrome://browser-region/locale/region.propertiesundefined
browser.contentHandlers.types.5.typeapplication/vnd.mozilla.maybe.feedundefined
browser.contentHandlers.types.5.urichrome://browser-region/locale/region.propertiesundefined
browser.contentblocking.cookies-site-data.ui.reject-trackers.enabledundefinedtrue
browser.contentblocking.cookies-site-data.ui.reject-trackers.recommendedundefinedtrue
browser.contentblocking.fastblock.control-center.ui.enabledundefinedtrue
browser.contentblocking.fastblock.ui.enabledundefinedtrue
browser.contentblocking.introCountundefined0
browser.contentblocking.rejecttrackers.control-center.ui.enabledundefinedtrue
browser.contentblocking.rejecttrackers.ui.enabledundefinedtrue
browser.contentblocking.rejecttrackers.ui.recommendedundefinedtrue
browser.contentblocking.reportBreakage.enabledundefinedtrue
browser.contentblocking.reportBreakage.urlundefinedhttps://tracking-protection-issues.herokuapp.com/new
browser.contentblocking.trackingprotection.control-center.ui.enabledundefinedtrue
browser.contentblocking.trackingprotection.ui.enabledundefinedtrue
browser.contentblocking.ui.enabledundefinedfalse
browser.ctrlTab.previewsfalseundefined
browser.ctrlTab.recentlyUsedOrderundefinedtrue
browser.fastblock.enabledundefinedfalse
browser.fastblock.timeoutundefined5000
browser.showQuitWarningfalseundefined
browser.startup.homepagechrome://branding/locale/browserconfig.propertiesabout:home
browser.tabs.remote.separatePrivilegedContentProcessundefinedfalse
browser.translation.enginebingGoogle
devtools.aboutdebugging.collapsibilities.installedExtensionundefinedfalse
devtools.aboutdebugging.collapsibilities.otherWorkerundefinedfalse
devtools.aboutdebugging.collapsibilities.serviceWorkerundefinedfalse
devtools.aboutdebugging.collapsibilities.sharedWorkerundefinedfalse
devtools.aboutdebugging.collapsibilities.tabundefinedfalse
devtools.aboutdebugging.collapsibilities.temporaryExtensionundefinedfalse
devtools.aboutdebugging.network-locationsundefined[]
devtools.aboutdebugging.new-enabledundefinedfalse
devtools.aboutdebugging.showSystemAddonsundefinedfalse
devtools.accessibility.enabledfalsetrue
devtools.browserconsole.htmlfalseundefined
devtools.debugger.component-stack-visibletrueundefined
devtools.debugger.features.autocomplete-expressionsundefinedfalse
devtools.debugger.features.component-paneundefinedfalse
devtools.debugger.features.component-stackfalseundefined
devtools.debugger.features.map-await-expressionundefinedfalse
devtools.debugger.features.map-expression-bindingsundefinedtrue
devtools.debugger.features.skip-pausingfalsetrue
devtools.inspector.chrome.three-pane-enabledundefinedfalse
devtools.inspector.fonteditor.enabledfalsetrue
devtools.inspector.fonthighlighter.enabledfalsetrue
devtools.promote.accessibilityundefined1
devtools.remote.adb.extensionIDundefinedadb@mozilla.org
devtools.responsive.leftAlignViewport.enabledundefinedfalse
devtools.responsive.show-setting-tooltipundefinedtrue
devtools.toolbox.selectedToolwebconsoleinspector
dom.animations-api.core.enabledfalsetrue
dom.animations-api.element-animate.enabledtrueundefined
dom.datatransfer.mozAtAPIsundefinedtrue
dom.events.asyncClipboardundefinedtrue
dom.events.asyncClipboard.dataTransferundefinedfalse
dom.events.testing.asyncClipboardundefinedfalse
dom.ipc.keepProcessesAlive.privilegedundefined1
dom.ipc.processCount.privilegedundefined1
dom.keyboardevent.dispatch_during_compositionfalsetrue
dom.payments.defaults.saveAddressundefinedtrue
dom.payments.defaults.saveCreditCardundefinedfalse
dom.pointer-lock.enabledundefinedtrue
dom.ua_widget.enabledundefinedfalse
dom.visualviewport.enabledundefinedfalse
dom.vr.process.enabledundefinedfalse
dom.vr.service.enabledundefinedfalse
dom.webcomponents.customelements.enabledfalsetrue
dom.webcomponents.shadowdom.enabledfalsetrue
dom.webgpu.enableundefinedfalse
editor.inline_table_editing.enabled_by_defaultundefinedfalse
editor.positioning.enabled_by_defaultundefinedfalse
editor.resizing.enabled_by_defaultundefinedfalse
extensions.getAddons.langpacks.urlundefinedhttps://services.addons.mozilla.org/api/v3/addons/language-tools/?app=firefox&type=language&appversion=%VERSION%
extensions.webextensions.background-delayed-startupfalsetrue
extensions.webextensions.enablePerformanceCountersundefinedfalse
extensions.webextensions.remotefalsetrue
extensions.webextensions.themes.enabledtrueundefined
geo.provider.use_gpsdfalseundefined
geo.wifi.urihttps://www.googleapis.com/geolocation/v1/geolocate?key=%GOOGLE_API_KEY%https://location.services.mozilla.com/v1/geolocate?key=%MOZILLA_API_KEY%
gfx.webrender.async-scene-buildtrueundefined
gfx.webrender.debug.show-overdrawundefinedfalse
gfx.webrender.dl.dump-contentundefinedfalse
gfx.webrender.dl.dump-parentundefinedfalse
gfx.webrender.force-disabledundefinedfalse
identity.fxaccounts.autoconfig.uriundefined
identity.fxaccounts.commands.enabledundefinedfalse
identity.fxaccounts.messages.enabledfalseundefined
intl.multilingual.enabledundefinedfalse
io.activity.enabledundefinedfalse
layers.omtp.enabledfalsetrue
layout.accessiblecaret.bar.enabledfalseundefined
layout.accessiblecaret.bar.width2.0undefined
layout.css.all-shorthand.enabledtrueundefined
layout.css.column-span.enabledfalseundefined
layout.css.motion-path.enabledundefinedfalse
layout.css.scrollbar-width.enabledundefinedfalse
layout.css.unset-value.enabledtrueundefined
layout.css.webkit-appearance.enabledfalseundefined
marionette.log.levelinfoInfo
marionette.log.truncateundefinedtrue
media.allowed-to-play.enabledundefinedfalse
media.autoplay.allow-extension-background-pagesundefinedtrue
media.autoplay.allow-mutedundefinedtrue
media.autoplay.ask-permissionundefinedfalse
media.autoplay.block-webaudioundefinedfalse
media.autoplay.defaultundefined0
media.autoplay.enabledtrueundefined
media.autoplay.enabled.user-gestures-neededundefinedfalse
media.av1.enabledundefinedfalse
media.media-capabilities.enabledundefinedtrue
media.media-capabilities.screen.enabledundefinedfalse
media.peerconnection.sdp.rust.compareundefinedfalse
media.peerconnection.sdp.rust.enabledundefinedfalse
media.setsinkid.enabledundefinedfalse
network.cookie.cookieBehavior0undefined
network.cookie.lifetime.days90undefined
network.cookie.prefsMigratedfalseundefined
network.cookie.quotaPerHostundefined150
network.dns.resolver-thread-extra-idle-time-secondsundefined60
network.http.send_window_sizeundefined1024
network.proxy.enable_wpad_over_dhcpundefinedtrue
network.trr.disable-ECSundefinedtrue
prio.publicKeyAundefined35AC1C7576C7C6EDD7FED6BCFC337B34D48CB4EE45C86BEEFB40BD8875707733
prio.publicKeyBundefined26E6674E65425B823F1F1D5F96E3BB3EF9E406EC7FBA7DEF8B08A35DD135AF50
privacy.trackingprotection.ui.enabledtrueundefined
security.csp.enabletrueundefined
security.csp.enableStrictDynamictrueundefined
security.csp.enable_violation_eventsfalseundefined
security.csp.experimentalEnabledfalseundefined
security.pki.mitm_detectedundefinedfalse
services.blocklist.update_enabledtrueundefined
services.settings.poll_intervalundefined86400
services.sync.engine.bookmarks.validation.enabledundefinedtrue
services.sync.engine.passwords.validation.enabledundefinedtrue
services.sync.prefs.sync.browser.contentblocking.enabledundefinedtrue
services.sync.prefs.sync.browser.ctrlTab.previewstrueundefined
services.sync.prefs.sync.browser.ctrlTab.recentlyUsedOrderundefinedtrue
services.sync.prefs.sync.network.cookie.lifetime.daystrueundefined
shield.savant.enabledfalseundefined
shield.savant.loglevelwarnundefined
svg.marker-improvements.enabledtrueundefined
urlclassifier.trackingAnnotationTableundefinedtest-track-simple,base-track-digest256
urlclassifier.trackingAnnotationWhitelistTableundefinedtest-trackwhite-simple,mozstd-trackwhite-digest256
webgl.webgl2-compat-modefalseundefined
Default pref Javascript files
PrefFirefox 62.0Firefox 63.0 beta 4
browser/omni.ja.d/defaults/preferences/debugger.jspresentpresent
browser/omni.ja.d/defaults/preferences/devtools-client.jspresentpresent
browser/omni.ja.d/defaults/preferences/devtools-startup.jspresentpresent
browser/omni.ja.d/defaults/preferences/firefox-branding.jspresentpresent
browser/omni.ja.d/defaults/preferences/firefox-l10n.jspresentpresent
browser/omni.ja.d/defaults/preferences/firefox.jspresentpresent
browser/omni.ja.d/defaults/preferences/webide.jspresentpresent
omni.ja.d/defaults/pref/marionette.jspresentpresent
omni.ja.d/defaults/pref/services-sync.jspresentpresent
omni.ja.d/greprefs.jspresentpresent