This article shows the difference between the default preferences of Firefox 144.0 beta 3 and Firefox 143.0.1. The diff table below is generated using my small script firefox-prefjs-surveyer.

Preference difference
PrefFirefox 144.0 beta 3Firefox 143.0.1
about.glean.redesign.enabled undefined false
app.normandy.test-prefs.bool undefined false
app.normandy.test-prefs.integer undefined 0
app.normandy.test-prefs.string undefined
app.releaseNotesURL https://www.mozilla.org/%LOCALE%/firefox/%VERSION%/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=whatsnew https://www.mozilla.org/%LOCALE%/firefox/%VERSION%beta/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=whatsnew
app.releaseNotesURL.aboutDialog https://www.mozilla.org/%LOCALE%/firefox/%VERSION%/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=about-dialog https://www.mozilla.org/%LOCALE%/firefox/%VERSION%beta/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=about-dialog
app.update.channel release beta
app.update.url.details https://www.mozilla.org/%LOCALE%/firefox/notes https://www.mozilla.org/%LOCALE%/firefox/beta/notes
app.update.url.manual https://www.mozilla.org/%LOCALE%/firefox/new?reason=manual-update https://www.mozilla.org/%LOCALE%/firefox/beta?reason=manual-update
browser.backup.scheduled.minimum-time-between-backups-seconds 3600 86400
browser.contextual-services.contextId.rotation-in-days 30 15
browser.ml.chat.page false true
browser.newtabpage.activity-stream.discoverystream.config {"api_key_pref":"extensions.pocket.oAuthConsumerKey","collapsible":true,"enabled":true} {"collapsible":true,"enabled":true}
browser.newtabpage.activity-stream.discoverystream.dailyBrief.enabled undefined false
browser.newtabpage.activity-stream.discoverystream.dailyBrief.sectionId undefined top_stories_section
browser.newtabpage.activity-stream.discoverystream.merino-provider.enabled true undefined
browser.newtabpage.activity-stream.discoverystream.onboardingExperience.dismissed false undefined
browser.newtabpage.activity-stream.discoverystream.onboardingExperience.enabled false undefined
browser.newtabpage.activity-stream.discoverystream.publisherFavicon.enabled false true
browser.newtabpage.activity-stream.discoverystream.refinedCardsLayout.enabled false true
browser.newtabpage.activity-stream.discoverystream.region-bff-config US,DE,CA,GB,IE,CH,AT,BE,IN,FR,IT,ES undefined
browser.newtabpage.activity-stream.discoverystream.reportAds.enabled false true
browser.newtabpage.activity-stream.discoverystream.spocMessageVariant undefined
browser.newtabpage.activity-stream.discoverystream.thumbsUpDown.region-thumbs-config US US, CA
browser.newtabpage.activity-stream.feeds.section.topstories.options {"api_key_pref":"extensions.pocket.oAuthConsumerKey","hidden":true,"provider_icon":"chrome://global/skin/icons/help.svg","provider_name":"Pocket","read_more_endpoint":"https://getpocket.com/explore/trending?src=fx_new_tab","stories_endpoint":"https://getpocket.cdn.mozilla.net/v3/firefox/global-recs?version=3&consumer_key=$apiKey&locale_lang=en-US&feed_variant=default_spocs_off","stories_referrer":"https://getpocket.com/recommendations","topics_endpoint":"https://getpocket.cdn.mozilla.net/v3/firefox/trending-topics?version=2&consumer_key=$apiKey&locale_lang=en-US","show_spocs":false} undefined
browser.newtabpage.activity-stream.newtabWallpapers.customWallpaper.theme undefined
browser.newtabpage.activity-stream.support.url https://support.mozilla.org/1/firefox/143.0.1/Linux/en-US/new-tab https://support.mozilla.org/1/firefox/144.0/Linux/en-US/new-tab
browser.newtabpage.activity-stream.telemetry.ut.events false true
browser.newtabpage.activity-stream.weather.placement undefined header
browser.newtabpage.activity-stream.widgets.lists.badge.enabled undefined false
browser.newtabpage.activity-stream.widgets.lists.badge.label undefined
browser.privatebrowsing.vpnpromourl https://vpn.mozilla.org/?utm_source=firefox-browser&utm_medium=firefox-%CHANNEL%-browser&utm_campaign=private-browsing-vpn-link undefined
browser.safebrowsing.provider.google5.enabled undefined false
browser.safebrowsing.provider.google5.gethashURL undefined https://safebrowsing.googleapis.com/v5/hashes:search?key=%GOOGLE_SAFEBROWSING_API_KEY%
browser.safebrowsing.provider.google5.lists undefined
browser.safebrowsing.provider.google5.updateURL undefined https://safebrowsing.googleapis.com/v5/hashLists:batchGet?key=%GOOGLE_SAFEBROWSING_API_KEY%
browser.search.suggest.ohttp.featureGate undefined false
browser.sessionstore.log.appender.file.logOnSuccess false true
browser.sessionstore.loglevel Warn Debug
browser.urlbar.allowSearchSuggestionsForSimpleOrigins undefined true
browser.urlbar.suggest.yelpRealtime undefined true
browser.urlbar.yelpRealtime.featureGate undefined false
browser.urlbar.yelpRealtime.minKeywordLength undefined 0
clipboard.copyPrivateDataToClipboardCloudOrHistory undefined false
devtools.anti-tracking.enabled undefined false
dom.block_external_protocol_navigation_from_sandbox true undefined
dom.document.edit_command.contentReadOnly.enabled true false
dom.document.edit_command.insertBrOnReturn.enabled true false
dom.element.commandfor.enabled false true
dom.event.keypress.key.allow_lone_surrogate true false
dom.events.script_execute.enabled true false
dom.ipc.processPrelaunch.startupDelayMs 1000 undefined
dom.media.webcodecs.batch-encoding-size undefined 1
dom.movebefore.enabled false true
dom.mutation_events.enabled false undefined
dom.mutation_events.forceEnable undefined
dom.object_embed.type_hint.enabled undefined false
dom.performance.event_timing.enable_interactionid false true
dom.screenorientation.allow-lock false true
dom.security.framebusting_intervention.enabled undefined true
dom.security.unexpected_system_load_telemetry_enabled false true
dom.shadowdom.referenceTarget.enabled undefined false
dom.storage_access.headers.enabled undefined false
dom.viewTransitions.enabled false true
dom.w3c_pointer_events.getcoalescedevents_only_in_securecontext false true
dom.webgpu.enabled false true
dom.webgpu.service-workers.enabled false true
dom.workers.throttling.enabled false true
extensions.InstallTriggerImpl.enabled false undefined
extensions.webcompat-reporter.enabled false true
gfx.webrender.dithering false true
javascript.options.baselinejit.offthread_compilation_strategy undefined 2
javascript.options.experimental.promise_try true undefined
javascript.options.experimental.upsert undefined true
layout.css.letter-spacing.model 0 2
layout.css.ruby.normalize-metrics-factor undefined 0
layout.dynamic-reflow-roots.enabled false true
mathml.math_shift.enabled undefined false
mathml.rtl_operator_mirroring.enabled undefined false
mathml.stixgeneral_operator_stretching.disabled true undefined
media.cubeb.force_mock_context undefined false
media.mkv.enabled undefined false
media.navigator.video.default_resize_mode 0 1
media.navigator.video.resize_mode.enabled false true
media.webrtc.enable_pq_dtls false true
media.webrtc.simulcast.vp9.enabled false true
network.android_doh.autoselect_enabled false undefined
network.auth.sspi_detect_hash undefined true
network.auth.use_redirect_for_retries false true
network.http.http2.max_stream_id undefined 125829120
network.http.http3.ecn_mark false true
network.http.http3.retry_different_ip_family false true
network.http.http3.use_nspr_for_io true false
network.http.retry_with_another_half_open false true
network.jar.record_failure_reason false true
network.lna.allow_top_level_navigation undefined true
network.lna.block_trackers false true
network.mimesniff.extra_moz_html_tags undefined false
network.predictor.enabled true false
network.proxy.testing_localhost_is_secure_when_hijacked false true
network.socket.ip_addr_any.disabled false true
network.trr.async_connInfo false true
network.trr.idle_timeout_for_http3_conn 30 400
pdfjs.enableComment false true
pdfjs.enableHighlightFloatingButton false true
pdfjs.enableOptimizedPartialRendering undefined false
print.cups.monochrome-gtk-simple.enabled undefined true
privacy.dynamic_firstparty.use_site.include_port false undefined
privacy.fingerprintingProtection.testing undefined false
privacy.trackingprotection.allow_list.hasUserInteractedWithETPSettings undefined false
remote.parent-navigation.enabled true undefined
security.disallow_non_local_systemprincipal_in_tests undefined false
security.disallow_privilegedabout_remote_script_loads true false
security.sdr.mechanism 0 1
security.ssl3.ecdhe_ecdsa_aes_128_sha true false
security.ssl3.ecdhe_ecdsa_aes_256_sha true false
services.sync.engine.bookmarks.validation.enabled undefined true
services.sync.engine.passwords.validation.enabled undefined true
toolkit.gecko-trace.enable undefined false
toolkit.rust-components.logging.crates undefined
toolkit.rust-components.logging.internal-level undefined Warn
toolkit.telemetry.enabled false true
ui.new-webcompat-reporter.send-more-info-link false true