This article shows the difference between the default preferences of Firefox 152.0.1 and Firefox 151.0.4. The diff table below is generated using my small script firefox-prefjs-surveyer.

Preference difference
PrefFirefox 151.0.4Firefox 152.0.1
app.releaseNotesURL https://www.mozilla.org/%LOCALE%/firefox/%VERSION%/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=whatsnew https://www.firefox.com/%LOCALE%/firefox/%VERSION%/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.firefox.com/%LOCALE%/firefox/%VERSION%/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=about-dialog
app.releaseNotesURL.prompt https://www.mozilla.org/%LOCALE%/firefox/%VERSION%/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=updateprompt https://www.firefox.com/%LOCALE%/firefox/%VERSION%/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-desktop&utm_campaign=updateprompt
browser.contentblocking.database.flushOnQuery.enabled undefined true
browser.contentblocking.report.proxy.enabled false undefined
browser.contentblocking.report.proxy_extension.url https://fpn.firefox.com/browser?utm_source=firefox-desktop&utm_medium=referral&utm_campaign=about-protections&utm_content=about-protections undefined
browser.contentsharing.newBadge.enabled true undefined
browser.ipProtection.fxa.useActivateFlow undefined true
browser.migrate.edge.enabled true false
browser.newtabpage.activity-stream.discoverystream.locale-weather-config en-US,en-GB,en-CA bg,cs,da,de,el,en-CA,en-GB,en-US,es-ES,et,fi,fr,hr,hu,is,it,lv,nb-NO,nl,pl,pt-PT,ro,sk,sl,sv-SE,tr
browser.newtabpage.activity-stream.discoverystream.region-weather-config US,CA 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
browser.newtabpage.activity-stream.feeds.sportsfeed undefined true
browser.newtabpage.activity-stream.privacyInfo.url https://support.mozilla.org/1/firefox/151.0.4/Linux/en-US/sponsor-privacy https://support.mozilla.org/1/firefox/152.0.1/Linux/en-US/sponsor-privacy
browser.newtabpage.activity-stream.sports.worldCup.matchesEndpoint undefined https://merino.services.mozilla.com/api/v1/wcs/matches
browser.newtabpage.activity-stream.sports.worldCup.teamsEndpoint undefined https://merino.services.mozilla.com/api/v1/wcs/teams
browser.newtabpage.activity-stream.support.url https://support.mozilla.org/1/firefox/151.0.4/Linux/en-US/new-tab https://support.mozilla.org/1/firefox/152.0.1/Linux/en-US/new-tab
browser.newtabpage.activity-stream.widgets.clocks.enabled undefined true
browser.newtabpage.activity-stream.widgets.clocks.hourFormat undefined
browser.newtabpage.activity-stream.widgets.clocks.size undefined large
browser.newtabpage.activity-stream.widgets.clocks.zones undefined
browser.newtabpage.activity-stream.widgets.focusTimer.size large
browser.newtabpage.activity-stream.widgets.lists.size large
browser.newtabpage.activity-stream.widgets.order undefined
browser.newtabpage.activity-stream.widgets.sportsWidget.enabled undefined true
browser.newtabpage.activity-stream.widgets.sportsWidget.interaction undefined false
browser.newtabpage.activity-stream.widgets.sportsWidget.live.enabled undefined false
browser.newtabpage.activity-stream.widgets.sportsWidget.size undefined
browser.newtabpage.activity-stream.widgets.system.clocks.enabled undefined false
browser.newtabpage.activity-stream.widgets.system.sportsWidget.enabled undefined false
browser.privatebrowsing.felt-privacy-v1 false true
browser.settings-redesign.enabled false true
browser.smartwindow.allowTables undefined true
browser.smartwindow.nova.enabled false undefined
browser.tabs.secondaryTextUnsupportedLocales ar,bn,bo,ckb,fa,gu,he,hi,ja,km,kn,ko,lo,mr,my,ne,pa,si,ta,te,th,ur,zh undefined
browser.toolbars.share-button.enabled undefined true
browser.urlbar.contextMenu.featureGate undefined false
browser.urlbar.trustPanel.breachAlerts undefined true
browser.urlbar.trustPanel.breachAlerts.featureGate undefined true
devtools.markup.showComments undefined true
devtools.responsive.dynamicToolbar.onTop undefined false
dom.editcontext.enabled undefined false
dom.geolocation.require_system_permission.enabled undefined false
dom.image.sizes_auto.enabled undefined true
dom.pointer-lock.unadjusted-movement.enabled undefined true
dom.webnotifications.actions.enabled false true
extensions.web_accessible_workers.deprecated_behavior undefined false
extensions.webextensions.allow_executeScript_in_moz_extension true false
extensions.webextensions.pageActionIconDarkModeFilter.enabled true false
gfx.webrender.debug.dl.dump-spatial-tree undefined false
gfx.will-change.ignore-opacity true undefined
image.jxl.enabled undefined false
javascript.options.experimental.capture_oom_stack_trace false true
javascript.options.wasm_cont_stack_arena_capacity undefined 8
javascript.options.wasm_cont_stack_size undefined 1048576
javascript.options.wasm_memory_debugging undefined false
layout.css.fake-webkit-scrollbar.disabled-domains undefined discord.com,shitposter.world
layout.css.field-sizing.enabled false true
layout.css.ruby.normalize-metrics-factor 0 100
layout.css.scroll-driven-animations.viewtimeline.enabled undefined false
media.audioFocus.webaudio.enabled undefined false
media.contextmenu.video-overlay-detection undefined false
media.eme.video.prefer-platform-decoder undefined false
media.ffmpeg.customized-buffer-allocation true undefined
media.getusermedia.camera.fake.no_capabilities undefined false
media.gmp-widevinecdm.allow-chromium-update undefined true
media.hardware-video-decoding-vulkan.enabled undefined false
media.mediacapabilities.legacy.allowlist undefined
media.mediacapabilities.legacy.enabled undefined false
media.mediacapabilities.webrtc-encode-smooth-override undefined 0
media.mediacapabilities.webrtc.enabled undefined false
media.mediacapabilities.webrtc.enabled.allowlist undefined
media.navigator.audio.use_transport_cc undefined true
media.privatebrowsing.metadata.enabled undefined false
media.videocontrols.picture-in-picture.auto-close.enabled undefined true
media.videocontrols.picture-in-picture.auto-close.timeoutMs undefined 1000
network.cookie.valueless_cookie undefined true
network.http.altsvc.oe false undefined
network.http.happy_eyeballs_connection_attempt_delay undefined 250
network.http.happy_eyeballs_resolution_delay undefined 50
network.http.http3.apple_fast_datapath undefined true
network.http.http3.hystart_alternative_css_baseline undefined false
network.http.http3.spurious_recovery undefined true
network.prefetch-next.force-valid-for undefined 300
network.ssl_tokens_cache_persistence undefined false
network.trr.add_additional_records true false
nimbus.profilesdatastoreservice.read.enabled false true
nimbus.profilesdatastoreservice.sync.enabled false true
pdfjs.enableOptimizedPartialRendering false true
print.cups.monochrome-gtk-simple.enabled true undefined
print.cups.monochrome.enabled true undefined
privacy.partition.always_partition_third_party_non_cookie_storage true undefined
privacy.partition.always_partition_third_party_non_cookie_storage.exempt_sessionstorage false undefined
privacy.reducePageProtection.infobar.enabled.pbmode false true
privacy.trackingprotection.content.annotation.list_names undefined
privacy.trackingprotection.content.protection.list_names undefined
privacy.trackingprotection.content.remote_settings.loglevel undefined Warn
privacy.trackingprotection.defer_annotation.enabled undefined false
security.webauthn.related_origin_requests_mode undefined 2
toolkit.zoomManager.zoomValues .3,.5,.67,.8,.9,1,1.1,1.2,1.33,1.5,1.7,2,2.4,3,4,5 .2,.3,.4,.5,.6,.7,.8,.9,1,1.1,1.2,1.3,1.4,1.5,1.6,1.7,1.8,1.9,2,2.2,2.4,2.6,2.8,3,4,5
ui.new-webcompat-reporter.reason-dropdown.randomized true undefined
webgl.out-of-process true undefined
webgl.out-of-process.force false undefined
webgl.out-of-process.worker true undefined
zoom.minPercent 30 20