This article shows the difference between the default preferences of Firefox 143.0.1 and Firefox 142.0.1. The diff table below is generated using my small script firefox-prefjs-surveyer.

Preference difference
PrefFirefox 143.0.1Firefox 142.0.1
apz.scrollbarbuttonrepeat.enabled true undefined
browser.contentanalysis.print_set_foreground_window undefined true
browser.contextual-services.contextId.rotation-in-days 0 30
browser.download.deletePrivateChosen false undefined
browser.download.enableDeletePrivate false true
browser.ipProtection.guardian.endpoint undefined https://vpn.mozilla.org/
browser.ipProtection.log undefined false
browser.ipProtection.variant undefined
browser.lna.warning.infoURL undefined https://support.mozilla.org/%LOCALE%/kb/control-personal-device-local-network-permissions-firefox
browser.ml.linkPreview.shift true false
browser.ml.pageAssist.enabled undefined false
browser.newtabpage.activity-stream.discoverystream.editorsPicksHeader.enabled false undefined
browser.newtabpage.activity-stream.discoverystream.essentialReadsHeader.enabled false undefined
browser.newtabpage.activity-stream.discoverystream.isCollectionDismissible true undefined
browser.newtabpage.activity-stream.discoverystream.personalization.override undefined false
browser.newtabpage.activity-stream.discoverystream.promoCard.enabled undefined false
browser.newtabpage.activity-stream.discoverystream.promoCard.visible undefined true
browser.newtabpage.activity-stream.discoverystream.recentSaves.enabled false undefined
browser.newtabpage.activity-stream.discoverystream.saveToPocketCard.enabled true undefined
browser.newtabpage.activity-stream.discoverystream.saveToPocketCardRegions undefined
browser.newtabpage.activity-stream.discoverystream.shortcuts.force_log.enabled undefined false
browser.newtabpage.activity-stream.discoverystream.shortcuts.personalization.locale-config en-US,en-GB,en-CA undefined
browser.newtabpage.activity-stream.discoverystream.shortcuts.personalization.region-config undefined
browser.newtabpage.activity-stream.discoverystream.sponsored-collections.enabled false undefined
browser.newtabpage.activity-stream.newtabShortcuts.refresh true undefined
browser.newtabpage.activity-stream.showRecentSaves true undefined
browser.newtabpage.activity-stream.support.url https://support.mozilla.org/1/firefox/142.0.1/Linux/en-US/new-tab https://support.mozilla.org/1/firefox/143.0.1/Linux/en-US/new-tab
browser.newtabpage.activity-stream.widgets.focusTimer.interaction undefined false
browser.newtabpage.activity-stream.widgets.focusTimer.showSystemNotifications undefined false
browser.newtabpage.activity-stream.widgets.lists.interaction undefined false
browser.newtabpage.activity-stream.widgets.lists.maxListItems undefined 100
browser.newtabpage.activity-stream.widgets.lists.maxLists undefined 10
browser.newtabpage.activity-stream.widgets.system.enabled undefined false
browser.newtabpage.sponsor-protection.enabled undefined true
browser.screenshots.folderList 1 4
browser.search.param.search_rich_suggestions fen undefined
browser.search.rustSelector.featureGate true undefined
browser.search.visualSearch.featureGate undefined false
browser.tabs.groups.hoverPreview.enabled undefined false
browser.tabs.groups.smart.enabled false true
browser.unexpectedScriptLoad.logLevel undefined Warn
browser.urlbar.fakespot.minKeywordLength 4 undefined
browser.urlbar.fakespot.suggestedIndex -1 undefined
browser.urlbar.importantDates.featureGate undefined false
browser.urlbar.market.featureGate undefined false
browser.urlbar.market.minKeywordLength undefined 0
browser.urlbar.suggest.fakespot true undefined
browser.urlbar.suggest.importantDates undefined true
browser.urlbar.suggest.realtimeOptIn undefined true
content.cors.use_triggering_principal undefined false
devtools.every-frame-target.enabled true undefined
devtools.webconsole.groupSimilarMessages undefined true
devtools.webconsole.groupWarningMessages true undefined
dom.custom_elements.relaxed_names.enabled undefined true
dom.disable_tab_focus_to_root_element true undefined
dom.movebefore.enabled undefined false
dom.private-attribution.submission.enabled true false
dom.quotaManager.loadQuotaFromSecondaryCache false true
dom.quotaManager.originInitialization.updateOriginMetadata false true
dom.serviceworkers.loadingCachedScriptOnWorkerThread.enabled undefined false
dom.webgpu.external-texture.enabled undefined false
extensions.formautofill.addresses.supportedCountries US,CA,GB,FR,DE US,CA,GB,FR,DE,BR,ES,JP
extensions.formautofill.creditCards.heuristics.fathom.highConfidenceThreshold 0.95 undefined
extensions.pocket.refresh.hideRecentSaves.enabled false undefined
extensions.userScripts.mv3.enabled true undefined
extensions.webextensions.userScripts.enabled true undefined
gfx.canvas.accelerated.max-export-surface-memory undefined 536870912
gfx.canvas.accelerated.max-export-surfaces undefined 100
gfx.skia.dithering undefined false
gfx.wayland.hdr.force-enabled undefined false
javascript.options.ducktyped_errors undefined false
javascript.options.experimental.import_attributes true undefined
javascript.options.objectfuse_for_global undefined true
javascript.options.wasm_exception_force_stack_trace undefined false
layout.css.details-content.enabled false true
layout.css.element-content-none.enabled false undefined
layout.css.grid-multi-pass-track-sizing.enabled false true
layout.css.moz-appearance.enabled undefined true
layout.css.moz-appearance.webidl.enabled undefined false
layout.css.moz-user-input.enabled false undefined
layout.css.overflow-moz-hidden-unscrollable.enabled true false
layout.css.scroll-state.enabled undefined false
layout.css.size-adjust.enabled true undefined
layout.css.text-autospace.enabled undefined false
layout.css.text-decoration-trim.enabled undefined false
layout.details.force-block-layout true false
messaging-system.profile.singleProfileMessaging.disable undefined true
network.dnsCacheExpirationGracePeriod 60 600
network.http.http3.enable_certificate_compression_brotli undefined true
network.http.http3.enable_certificate_compression_zlib undefined true
network.http.http3.enable_certificate_compression_zstd undefined true
pdfjs.enableComment undefined false
pdfjs.highlightEditorColors yellow=#FFFF98,green=#53FFBC,blue=#80EBFF,pink=#FFCBE6,red=#FF4F5F yellow=#FFFF98,green=#53FFBC,blue=#80EBFF,pink=#FFCBE6,red=#FF4F5F,yellow_HCM=#FFFFCC,green_HCM=#53FFBC,blue_HCM=#80EBFF,pink_HCM=#F6B8FF,red_HCM=#C50043
permissions.default.local-network undefined 0
permissions.default.localhost undefined 0
security.block_parent_unrestricted_js_loads.temporary undefined false
security.csp.reporting.limit.timespan 2 undefined
security.hide_parent_unrestricted_js_loads_warning.temporary undefined false
security.mixed_content.upgrade_display_content.audio true undefined
security.mixed_content.upgrade_display_content.image true undefined
security.mixed_content.upgrade_display_content.video true undefined
security.parent_unrestricted_js_loads.skip_jshacks undefined false
security.pki.netscape_step_up_policy 1 undefined
services.sync.prefs.sync.browser.ipProtection.enabled undefined true
sidebar.verticalTabs.dragToPinPromo.dismissed undefined false
svg.embedder-prefers-color-scheme.content.enabled true undefined
urlclassifier.enabled_mode undefined 3