This article shows the difference between the default preferences of Firefox 160.0 beta 5 and Firefox 159.0.1. The diff table below is generated using my small script firefox-prefjs-surveyer.

Preference difference
PrefFirefox 159.0.1Firefox 160.0 beta 5
app.releaseNotesURL https://www.firefox.com/%LOCALE%/firefox/%VERSION%/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=whatsnew https://www.firefox.com/%LOCALE%/firefox/%VERSION%beta/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=whatsnew
app.releaseNotesURL.aboutDialog https://www.firefox.com/%LOCALE%/firefox/%VERSION%/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=about-dialog https://www.firefox.com/%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.fireButton.enabled undefined false
browser.fireButton.flow undefined panel
browser.ipProtection.locationButtonBadgeDismissed false undefined
browser.ipProtection.openedPanelSince160 undefined false
browser.ipProtection.siteExceptionsHintsEnabled true undefined
browser.ipProtection.siteInclusionPromptShown undefined false
browser.mini-window.enabled false true
browser.newtabpage.activity-stream.discoverystream.region-weather-config AT,BE,BG,CA,CH,CY,CZ,DE,DK,EE,ES,FI,FR,GB,GR,HR,HU,IE,IS,IT,LI,LT,LV,MT,NL,NO,PL,PT,RO,SE,SI,SK,US AT,BE,BG,CA,CH,CY,CZ,DE,DK,EE,ES,FI,FR,GB,GR,HR,HU,IE,IS,IT,LI,LT,LV,MT,NL,NO,PL,PT,RO,SE,SG,SI,SK,US
browser.newtabpage.activity-stream.feeds.extensionwidgetsfeed undefined true
browser.newtabpage.activity-stream.feeds.travelfeed undefined true
browser.newtabpage.activity-stream.privacyInfo.url https://support.mozilla.org/1/firefox/159.0.1/Linux/en-US/sponsor-privacy https://support.mozilla.org/1/firefox/160.0/Linux/en-US/sponsor-privacy
browser.newtabpage.activity-stream.sectionsLearnMore.url https://support.mozilla.org/1/firefox/159.0.1/Linux/en-US/firefox-new-tab-personalization https://support.mozilla.org/1/firefox/160.0/Linux/en-US/firefox-new-tab-personalization
browser.newtabpage.activity-stream.support.url https://support.mozilla.org/1/firefox/159.0.1/Linux/en-US/new-tab https://support.mozilla.org/1/firefox/160.0/Linux/en-US/new-tab
browser.newtabpage.activity-stream.telemetry.privatePing.dwellTime.enabled undefined false
browser.newtabpage.activity-stream.telemetry.privatePing.dwellTime.noiseScale undefined 0.05
browser.newtabpage.activity-stream.telemetry.privatePing.maxSubmissionDelayMs 5000 6000
browser.newtabpage.activity-stream.telemetry.privatePing.minSubmissionDelayMs undefined 1000
browser.newtabpage.activity-stream.topSitesGroupedPins false true
browser.newtabpage.activity-stream.unifiedAds.tiles.ohttpImages.enabled undefined false
browser.newtabpage.activity-stream.widgets.horoscopes.enabled undefined false
browser.newtabpage.activity-stream.widgets.horoscopes.interaction undefined false
browser.newtabpage.activity-stream.widgets.horoscopes.size undefined
browser.newtabpage.activity-stream.widgets.solitaire.enabled undefined false
browser.newtabpage.activity-stream.widgets.solitaire.interaction undefined false
browser.newtabpage.activity-stream.widgets.solitaire.size undefined
browser.newtabpage.activity-stream.widgets.system.horoscopes.enabled undefined false
browser.newtabpage.activity-stream.widgets.system.solitaire.enabled undefined false
browser.newtabpage.activity-stream.widgets.system.travel.enabled undefined false
browser.newtabpage.activity-stream.widgets.travel.enabled undefined false
browser.newtabpage.activity-stream.widgets.travel.interaction undefined false
browser.newtabpage.activity-stream.widgets.travel.size undefined
browser.preferences.notifications-section.enabled undefined false
browser.protectionsPanelRedesign.enabled undefined false
browser.search.configV3.featureGate undefined false
browser.sessionstore.encryption.available undefined false
browser.sessionstore.encryption.enabled undefined false
browser.smartwindow.aitab.menus undefined false
browser.smartwindow.autoTabGrouping.maxCandidateTabs undefined 200
browser.smartwindow.autoTabGrouping.nonEnglishThresholdInt undefined 550
browser.smartwindow.autoTabGrouping.supportedLocales undefined en,fr
browser.smartwindow.resumeCards.enabled false true
browser.tabs.groups.saveHintShownCount undefined 0
browser.toolbars.tab-groups.enabled undefined false
browser.urlbar.extension.timeout 400 undefined
browser.urlbar.quicksuggest.contextualOptIn false undefined
browser.urlbar.quicksuggest.contextualOptIn.dismissedCount 0 undefined
browser.urlbar.quicksuggest.contextualOptIn.firstReshowAfterPeriodDays 7 undefined
browser.urlbar.quicksuggest.contextualOptIn.impressionCount 0 undefined
browser.urlbar.quicksuggest.contextualOptIn.impressionDaysLimit 5 undefined
browser.urlbar.quicksuggest.contextualOptIn.impressionLimit 20 undefined
browser.urlbar.quicksuggest.contextualOptIn.secondReshowAfterPeriodDays 14 undefined
browser.urlbar.quicksuggest.contextualOptIn.thirdReshowAfterPeriodDays 60 undefined
browser.urlbar.suggest.temporal undefined true
browser.urlbar.suggest.temporal.seasonal undefined true
browser.urlbar.temporal.featureGate undefined false
devtools.application.speculativeLoads undefined false
dom.element.blocking.timeout-ms undefined 5000
dom.ipc.validatePrincipal.testing.allowContentSystemDocuments undefined false
dom.links.sync_fragment_navigation undefined true
dom.quotaManager.encryption.enabled undefined false
dom.quota_exceeded_error.enabled undefined false
dom.speculation_rules.prefetch.dry_run undefined false
dom.storage.shadow_writes false undefined
dom.template-for.enabled undefined false
dom.text_fragments.enabled true undefined
dom.viewTransitions.cross-document.pageswap-timeout-ms undefined 4000
dom.viewTransitions.hit-testing undefined 2
extensions.formautofill.addresses.supported detect on
extensions.formautofill.useml.hint.fields undefined ["email","tel","tel-country-code","street-address","address-line1","address-line2","address-line3","postal-code","address-level1","address-level2","organization","country","name","given-name","family-name","cc-name","cc-type"]
extensions.formautofill.useml.useHeuristicsForOther undefined false
extensions.web_accessible_workers.deprecated_behavior false undefined
extensions.webcompat-reporter.enabled false undefined
extensions.webcompat-reporter.newIssueEndpoint https://webcompat.com/issues/new undefined
gfx.canvas.colorspace.enabled undefined false
gfx.webrender.enforce-embed-policy undefined true
gfx.webrender.svg-activity.mostly-active-percent undefined 0
gfx.webrender.svg-images.opacity undefined false
gfx.webrender.svg-mask-propagates-activity undefined false
gfx.webrender.svg-shapes.blend undefined false
gfx.webrender.svg-shapes.ellipses undefined false
gfx.webrender.svg-shapes.gradients undefined false
gfx.webrender.svg-shapes.strokes undefined false
gfx.webrender.svg-simple-clips undefined false
gfx.webrender.svg-text undefined false
gfx.webrender.svg-text.fill-opacity undefined false
image.webp.scaled-decoding.enabled undefined true
image.webp.scaled-decoding.min-factor undefined 2.5
javascript.options.experimental.inline_simple_field_initializers undefined false
javascript.options.other_processes_disable_jit undefined false
layout.accessiblecaret.allow_dragging_across_other_caret true undefined
layout.css.transitions-override-ua undefined false
layout.css.webkit-input-placeholder.enabled undefined true
layout.css.webkit-line-clamp.block.enabled false undefined
layout.css.webkit-line-clamp.skip-paint false true
layout.scrolled-area-changed.content.enabled undefined false
media.lazy_loading.enabled undefined false
media.videocontrols.picture-in-picture.playback-speed.enabled false true
media.webspeech.recognition.enable false true
memory.lazypurge.maximum_delay 5000 undefined
memory.lazypurge.minimum_idle_budget 10 undefined
network.dnsCacheEntries 1600 3200
network.dnsNegativeCacheExpirationGracePeriod 60 600
network.http.akamai_waf_telemetry.enabled undefined true
pdfjs.disableWorkerRendering undefined true
pdfjs.rendererWorkerCount undefined 1
permissions.default.register-protocol-handler undefined 0
print.experimental.skpdf true undefined
print.windows.skia-gdi.enabled undefined true
print.windows.skia-gdi.raster-dpi undefined 300
security.lockstore.unlock.enabled undefined false
sidebar.animation.duration-ms 200 undefined
sidebar.animation.expand-on-hover.duration-ms 400 200
signon.storage.rust.enabled false true
signon.storage.rust.maxPrimaryPasswordDeferrals undefined 3
signon.storage.rust.primaryPasswordDeferrals undefined 0
svg.use-element.block-inline-event-handlers undefined false
telemetry.fog.init_on_shutdown true false
toolkit.telemetry.enabled false true
ui.mouse.radius.visitedWeight 120 undefined
ui.touch.radius.visitedWeight 120 undefined
webgl.enable-surface-texture true undefined