This is difference between the default preference of Firefox 59.0 beta 7 and one of 58.0.1.

Preference difference
PrefFirefox 58.0.1Firefox 59.0 beta 7
accessibility.usebrailledisplayundefined
alerts.useSystemBackendundefinedtrue
application.use_ns_plugin_finderfalseundefined
apz.pinch_lock.modeundefined1
apz.pinch_lock.scoll_lock_thresholdundefined0.03125
apz.pinch_lock.span_breakout_thresholdundefined0.03125
apz.pinch_lock.span_lock_thresholdundefined0.03125
autocomplete.grab_during_popuptrueundefined
autocomplete.ungrab_during_mode_switchtrueundefined
browser.chrome.toolbar_style2undefined
browser.helperApps.alwaysAsk.forcefalseundefined
browser.popups.showPopupBlockertrueundefined
camera.control.face_detection.enabledtrueundefined
capability.policy.default.SOAPCall.invokeVerifySourceHeaderallAccessundefined
datareporting.healthreport.about.reportUrlhttps://fhr.cdn.mozilla.net/%LOCALE%/v4/undefined
devtools.debugger.breakpoints-visibleundefinedtrue
devtools.debugger.call-stack-visiblefalsetrue
devtools.debugger.expressions-visibleundefinedtrue
devtools.debugger.features.breakpoints-dropdownundefinedtrue
devtools.debugger.features.chrome-scopesundefinedfalse
devtools.debugger.features.code-coverageundefinedfalse
devtools.debugger.features.code-foldingundefinedfalse
devtools.debugger.features.event-listenersundefinedfalse
devtools.debugger.features.map-scopesundefinedfalse
devtools.debugger.features.outlineundefinedtrue
devtools.debugger.features.project-text-searchtrueundefined
devtools.debugger.features.remove-command-bar-optionsundefinedfalse
devtools.debugger.features.workersundefinedtrue
devtools.debugger.scopes-visibleundefinedtrue
devtools.debugger.workers-visibleundefinedtrue
devtools.devedition.promo.enabledfalsetrue
devtools.gridinspector.showNegativeLineNumbersfalseundefined
devtools.highlighter.writingModeAdjustundefinedfalse
devtools.inspector.flexboxHighlighter.enabledundefinedfalse
devtools.inspector.split-rule-enabledundefinedfalse
devtools.inspector.split-sidebar-toggleundefinedfalse
devtools.migration.warningstrueundefined
devtools.performance.new-panel-enabledundefinedfalse
devtools.remote.wifi.visibletrueundefined
devtools.telemetry.supported_performance_markscontentInteractive,navigationInteractive,navigationLoaded,visuallyLoaded,fullyLoaded,mediaEnumerated,scanEndundefined
devtools.webconsole.sidebarToggleundefinedfalse
dom.animations-api.pending-member.enabledundefinedtrue
dom.clients.openwindow_favors_same_processundefinedtrue
dom.disable_window_status_changetrueundefined
dom.event.coalesce_mouse_movefalsetrue
dom.flyweb.enabledfalseundefined
dom.idle-observers-api.enabledtrueundefined
dom.idle_period.throttled_length10000undefined
dom.min_tracking_background_timeout_value100004
dom.registerContentHandler.enabledundefinedtrue
dom.select_popup_in_content.enabledundefinedfalse
dom.serviceWorkers.openWindow.enabledtrueundefined
dom.sysmsg.enabledfalseundefined
dom.vr.controller.enumerate.intervalundefined1000
dom.vr.display.enumerate.intervalundefined5000
dom.vr.inactive.timeoutundefined5000
dom.vr.oculus.invisible.enabledundefinedtrue
dom.vr.oculus.present.timeout10000500
dom.vr.oculus.quit.timeout3000010000
dom.w3c_pointer_events.enabledfalsetrue
dom.webapps.useCurrentProfilefalseundefined
dom.webcomponents.enabledfalseundefined
dom.webcomponents.shadowdom.enabledundefinedfalse
extensions.formautofill.creditCards.availablefalsetrue
extensions.formautofill.section.enabledundefinedtrue
extensions.formautofill.supportRTLundefinedtrue
extensions.formautofill.supportedCountriesundefinedUS,CA,DE
extensions.getAddons.maxResults15undefined
extensions.getAddons.recommended.urlhttps://services.addons.mozilla.org/%LOCALE%/%APP%/api/%API_VERSION%/list/recommended/all/%MAX_RESULTS%/%OS%/%VERSION%?src=firefoxundefined
extensions.getAddons.search.urlhttps://services.addons.mozilla.org/%LOCALE%/firefox/api/%API_VERSION%/search/%TERMS%/all/%MAX_RESULTS%/%OS%/%VERSION%/%COMPATIBILITY_MODE%?src=firefoxundefined
extensions.webextensions.tabhide.enabledundefinedfalse
font.name-list.emojiundefinedEmojiOne Mozilla
full-screen-api.ignore-widgetsundefinedfalse
general.useragent.localeen-USundefined
gfx.downloadable_fonts.keep_color_bitmapsundefinedfalse
gfx.webrender.allundefinedfalse
gfx.webrender.blob-imagesfalse2
gfx.webrender.debug.compact-profilerundefinedfalse
gfx.webrender.debug.disable-batchingundefinedfalse
gfx.webrender.debug.epochsundefinedfalse
gfx.webrender.debug.gpu-sample-queriesundefinedfalse
gfx.webrender.debug.gpu-time-queriesundefinedfalse
gfx.webrender.hit-testundefinedfalse
identity.fxaccounts.remote.connectdevice.uriundefinedhttps://accounts.firefox.com/connect_another_device?service=sync&context=fx_desktop_v3
image.mem.sharedfalse2
images.ditherautoundefined
intl.charset.fallback.utf8_for_fileundefinedfalse
intl.locale.matchOSfalseundefined
javascript.options.mem.gc_refresh_frame_slices_enabledtrueundefined
javascript.options.spectre.index_maskingundefinedfalse
layers.advanced.text-layers2undefined
layers.gralloc.disablefalseundefined
layers.omtp.force-syncfalseundefined
layers.omtp.paint-workersundefined1
layout.css.grid.enabledtrueundefined
layout.css.moz-document.content.enabledundefinedtrue
layout.css.overscroll-behavior.enabledundefinedtrue
layout.display-list.retain.chromeundefinedfalse
media.cache.resource-index8192undefined
media.eme.hdcp-policy-check.enabledundefinedfalse
media.getusermedia.aec_delay_agnostictrueundefined
media.getusermedia.agc13
media.getusermedia.playout_delay50undefined
media.getusermedia.screensharing.allowed_domainswebex.com,*.webex.com,ciscospark.com,*.ciscospark.com,projectsquared.com,*.projectsquared.com,*.room.co,room.co,beta.talky.io,talky.io,*.clearslide.com,appear.in,*.appear.in,tokbox.com,*.tokbox.com,*.sso.francetelecom.fr,*.si.francetelecom.fr,*.sso.infra.ftgroup,*.multimedia-conference.orange-business.com,*.espacecollaboration.orange-business.com,free.gotomeeting.com,g2m.me,*.g2m.me,*.mypurecloud.com,*.mypurecloud.com.au,spreed.me,*.spreed.me,*.spreed.com,air.mozilla.org,*.circuit.com,*.yourcircuit.com,circuit.siemens.com,yourcircuit.siemens.com,circuitsandbox.net,*.unify.com,tandi.circuitsandbox.net,*.ericsson.net,*.cct.ericsson.net,*.opentok.com,*.conf.meetecho.com,meet.jit.si,*.meet.jit.si,web.stage.speakeasyapp.net,web.speakeasyapp.net,*.hipchat.me,*.beta-wspbx.com,*.wspbx.com,*.unifiedcloudit.com,*.smartboxuc.com,*.smartbox-uc.com,*.panterranetworks.com,pexipdemo.com,*.pexipdemo.com,pex.me,*.pex.me,*.rd.pexip.com,1click.io,*.1click.io,*.fuze.com,*.fuzemeeting.com,*.thinkingphones.com,gotomeeting.com,*.gotomeeting.com,gotowebinar.com,*.gotowebinar.com,gototraining.com,*.gototraining.com,citrix.com,*.citrix.com,expertcity.com,*.expertcity.com,citrixonline.com,*.citrixonline.com,g2m.me,*.g2m.me,gotomeet.me,*.gotomeet.me,gotomeet.at,*.gotomeet.at,miriadaxdes.miriadax.net,certificacion.miriadax.net,miriadax.net,*.wire.com,sylaps.com,*.sylaps.com,bluejeans.com,*.bluejeans.com,*.a.bluejeans.com,*.bbcollab.comundefined
media.navigator.load_adapttrueundefined
media.navigator.load_adapt.avg_seconds3undefined
media.navigator.load_adapt.encoder_onlytrueundefined
media.navigator.load_adapt.high_load0.90undefined
media.navigator.load_adapt.low_load0.40undefined
media.navigator.load_adapt.measure_interval1000undefined
media.navigator.video.default_minfps10undefined
media.peerconnection.rtpsourcesapi.enabledundefinedtrue
media.peerconnection.video.h264_enabledfalseundefined
media.raw.enabledtrueundefined
media.seamless-loopingundefinedtrue
media.webvtt.regions.enabledfalsetrue
network.activity.blipIntervalMilliseconds0undefined
network.activity.intervalMillisecondsundefined0
network.auth.subresource-img-cross-origin-http-auth-allowtruefalse
network.http.rcwn.enabledfalsetrue
network.http.referer.defaultPolicyundefined3
network.http.referer.defaultPolicy.pbmodeundefined2
network.http.referer.userControlPolicy3undefined
network.http.sendOriginHeaderundefined0
network.http.tailing.total-maxundefined45000
network.http.throttle.hold-time-msundefined800
network.http.throttle.max-time-msundefined500
network.http.throttle.read-interval-msundefined500
network.http.throttle.read-limit-bytesundefined8000
network.http.throttle.resume-background-in1000undefined
network.http.throttle.time-window3000undefined
network.http.throttle.versionundefined1
network.protocol-handler.external.htpundefinedfalse
network.protocol-handler.external.htpsundefinedfalse
network.tcp.tcp_fastopen_http_check_for_stalls_only_if_idle_forundefined10
network.tcp.tcp_fastopen_http_stalls_limitundefined3
network.tcp.tcp_fastopen_http_stalls_timeoutundefined20
notification.feature.enabledfalseundefined
prefs.converted-to-utf8falseundefined
print.always_cache_old_presfalseundefined
print.print_colortrueundefined
print.print_extra_margin0undefined
print.print_in_colorundefinedtrue
print.print_landscapefalseundefined
print.print_paper_size0undefined
privacy.reduceTimerPrecisionfalsetrue
privacy.spoof_englishundefined0
profile.confirm_automigrationtrueundefined
profile.migration_behavior0undefined
profile.migration_directoryundefined
profile.seconds_until_defunct-1undefined
security.checkloaduritrueundefined
security.csp.enable_violation_eventsundefinedfalse
security.data_uri.block_toplevel_data_uri_navigationsfalsetrue
security.insecure_connection_icon.enabledundefinedfalse
security.insecure_connection_icon.pbmode.enabledundefinedfalse
security.mixed_content.block_object_subrequestundefinedfalse
security.mixed_content.hsts_priming_cache_timeout604800undefined
security.mixed_content.hsts_priming_request_timeout2000undefined
security.mixed_content.send_hsts_primingfalseundefined
security.mixed_content.use_hstsfalseundefined
security.signed_app_signatures.policyundefined2
security.tls.enable_0rtt_datafalsetrue
security.tls.version.max34
security.use_sqldbtrueundefined
security.xpconnect.plugin.unrestrictedtrueundefined
services.sync.engine.tabs.filteredUrls^(about:.*|resource:.*|chrome:.*|wyciwyg:.*|file:.*|blob:.*)$^(about:.*|resource:.*|chrome:.*|wyciwyg:.*|file:.*|blob:.*|moz-extension:.*)$
services.sync.log.loggerundefinedDebug
services.sync.log.logger.addonutilsDebugundefined
services.sync.log.logger.authenticatorDebugundefined
services.sync.log.logger.declinedDebugundefined
services.sync.log.logger.engineundefinedDebug
services.sync.log.logger.engine.addonsDebugundefined
services.sync.log.logger.engine.addressesDebugundefined
services.sync.log.logger.engine.appsDebugundefined
services.sync.log.logger.engine.bookmarksDebugundefined
services.sync.log.logger.engine.clientsDebugundefined
services.sync.log.logger.engine.creditcardsDebugundefined
services.sync.log.logger.engine.extension-storageDebugundefined
services.sync.log.logger.engine.formsDebugundefined
services.sync.log.logger.engine.historyDebugundefined
services.sync.log.logger.engine.passwordsDebugundefined
services.sync.log.logger.engine.prefsDebugundefined
services.sync.log.logger.engine.tabsDebugundefined
services.sync.log.logger.identityDebugundefined
services.sync.log.logger.network.resourcesDebugundefined
services.sync.log.logger.service.mainDebugundefined
services.sync.log.logger.statusDebugundefined
services.sync.log.rootLoggerDebugundefined
stagefright.disabledfalseundefined
stagefright.force-enabledfalseundefined
toolkit.telemetry.hybridContent.enabledundefinedtrue
ui.allow_platform_file_pickertrueundefined
ui.key.saveLink.shifttrueundefined
urlclassifier.disallow_completionstest-malware-simple,test-harmful-simple,test-phish-simple,test-unwanted-simple,test-track-simple,test-trackwhite-simple,test-block-simple,goog-downloadwhite-digest256,base-track-digest256,mozstd-trackwhite-digest256,content-track-digest256,mozplugin-block-digest256,mozplugin2-block-digest256,block-flash-digest256,except-flash-digest256,allow-flashallow-digest256,except-flashallow-digest256,block-flashsubdoc-digest256,except-flashsubdoc-digest256,except-flashinfobar-digest256test-malware-simple,test-harmful-simple,test-phish-simple,test-unwanted-simple,test-track-simple,test-trackwhite-simple,test-block-simple,goog-downloadwhite-digest256,base-track-digest256,mozstd-trackwhite-digest256,content-track-digest256,mozplugin-block-digest256,mozplugin2-block-digest256,block-flash-digest256,except-flash-digest256,allow-flashallow-digest256,except-flashallow-digest256,block-flashsubdoc-digest256,except-flashsubdoc-digest256,except-flashinfobar-digest256,goog-passwordwhite-proto
viewmanager.do_doublebufferingtrueundefined
webchannel.allowObject.urlWhitelisthttps://accounts.firefox.com https://content.cdn.mozilla.net https://input.mozilla.org https://support.mozilla.org https://install.mozilla.orghttps://content.cdn.mozilla.net https://input.mozilla.org https://support.mozilla.org https://install.mozilla.org
webgl.max-contextsundefined32
webgl.max-contexts-per-principalundefined16
Default pref Javascript files
PrefFirefox 58.0.1Firefox 59.0 beta 7
browser/omni.ja.d/defaults/preferences/debugger.jspresentpresent
browser/omni.ja.d/defaults/preferences/devtools-startup-prefs.jspresentpresent
browser/omni.ja.d/defaults/preferences/devtools.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-prefs.jspresentpresent
omni.ja.d/defaults/pref/marionette.jspresentpresent
omni.ja.d/defaults/pref/services-sync.jspresentpresent
omni.ja.d/greprefs.jspresentpresent