This is difference between the default preference of Firefox 115.0 beta 3 and one of 114.0.1. This diff table is generated with my small script firefox-prefjs-surveyer.

Preference difference
PrefFirefox 115.0.1Firefox 115.0 beta 3
accessibility.cache.enabled true undefined
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-browser&utm_campaign=whatsnew https://www.mozilla.org/%LOCALE%/firefox/%VERSION%beta/releasenotes/?utm_source=firefox-browser&utm_medium=firefox-browser&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.bookmarks.editDialog.delayedApply.enabled true undefined
browser.cache.offline.enable true undefined
browser.contentblocking.features.strict tp,tpPrivate,cookieBehavior5,cookieBehaviorPBM5,cm,fp,stp,emailTP,emailTPPrivate,lvl2,lvl2PBM,rp,rpTop,ocsp,qps,qpsPBM tp,tpPrivate,cookieBehavior5,cookieBehaviorPBM5,cm,fp,stp,emailTP,emailTPPrivate,lvl2,rp,rpTop,ocsp,qps,qpsPBM
browser.display.force_inline_alttext false undefined
browser.download.improvements_to_download_panel true undefined
browser.migrate.bookmarks-file.enabled undefined true
browser.migrate.chrome.payment_methods.enabled undefined true
browser.newtabpage.activity-stream.telemetry.ut.events false true
browser.opaqueResponseBlocking false true
browser.opaqueResponseBlocking.filterFetchResponse undefined 2
browser.opaqueResponseBlocking.javascriptValidator false true
browser.startup.homepage.abouthome_cache.enabled false true
browser.tabs.searchclipboardfor.middleclick undefined true
browser.topsites.contile.sov.enabled undefined true
browser.translations.alwaysTranslateLanguages undefined
browser.translations.chaos.errors undefined false
browser.translations.chaos.timeoutMS undefined 0
browser.translations.enable false true
browser.translations.neverTranslateLanguages undefined
browser.urlbar.addons.featureGate undefined false
browser.urlbar.addons.minKeywordLength undefined 0
browser.urlbar.quickactions.enabled undefined true
browser.urlbar.quickactions.showPrefs undefined true
browser.urlbar.shortcuts.quickactions undefined true
browser.urlbar.showSearchTerms.featureGate false true
browser.urlbar.suggest.addons undefined true
browser.urlbar.suggest.quickactions undefined true
browser.urlbar.trending.featureGate undefined true
cookiebanners.ui.desktop.enabled false true
devtools.debugger.auto-black-box true undefined
devtools.debugger.component-visible false undefined
devtools.debugger.features.async-stepping false undefined
devtools.debugger.features.blackbox-lines false undefined
devtools.debugger.features.chrome-scopes false undefined
devtools.debugger.features.code-coverage false undefined
devtools.debugger.features.column-breakpoints true undefined
devtools.debugger.features.dom-mutation-breakpoints true undefined
devtools.debugger.features.event-listeners-breakpoints true undefined
devtools.debugger.features.frame-step true undefined
devtools.debugger.features.overlay true undefined
devtools.debugger.features.remove-command-bar-options false undefined
devtools.debugger.features.root true undefined
devtools.debugger.features.shortcuts true undefined
devtools.debugger.features.workers true undefined
devtools.debugger.features.xhr-breakpoints true undefined
devtools.debugger.hide-ignored-sources undefined false
devtools.debugger.pretty-print-enabled true undefined
devtools.debugger.threads-visible undefined true
devtools.debugger.ui.panes-instruments-width 300 undefined
devtools.debugger.ui.panes-visible-on-startup false undefined
devtools.debugger.ui.panes-workers-and-sources-width 200 undefined
devtools.debugger.ui.variables-only-enum-visible false undefined
devtools.debugger.ui.variables-searchbox-visible false undefined
devtools.debugger.ui.variables-sorting-enabled true undefined
devtools.debugger.workers false undefined
devtools.debugger.workers-visible false undefined
devtools.experiment.f12.shortcut_disabled false undefined
devtools.f12_enabled undefined true
devtools.netmonitor.har.multiple-pages undefined false
docshell.shistory.bfcache.ship_allow_beforeunload_listeners false true
dom.document.edit_command.contentReadOnly.enabled true false
dom.document.edit_command.insertBrOnReturn.enabled true false
dom.event.wheel-event-groups.enabled false true
dom.indexedDB.privateBrowsing.enabled false true
dom.media.mozPreservesPitch.enabled true false
dom.workers.importScripts.enforceStrictMimeType false true
editor.join_split_direction.compatible_with_the_other_browsers false true
extensions.InstallTrigger.enabled true false
extensions.browser_style_mv3.same_as_mv2 true false
extensions.quarantinedDomains.enabled undefined true
extensions.quarantinedDomains.list undefined
extensions.webcompat-reporter.enabled false true
fission.enforceBlocklistedPrefsInSubprocesses false true
font.size.systemFontScale 100 undefined
general.utility-process.startup_timeout_ms 5000 undefined
geo.provider.network.url https://www.googleapis.com/geolocation/v1/geolocate?key=%GOOGLE_LOCATION_SERVICE_API_KEY% https://location.services.mozilla.com/v1/geolocate?key=%MOZILLA_API_KEY%
gfx.webrender.dcomp-apply-1704954 true undefined
intl.ime.hack.on_any_apps.fire_key_events_for_composition false undefined
intl.ime.hack.on_ime_unaware_apps.fire_key_events_for_composition false undefined
javascript.options.experimental.enable_array_from_async false true
javascript.options.experimental.enable_change_array_by_copy false true
layout.css.allow-mixed-page-sizes false true
layout.css.always-repaint-on-unvisited true undefined
layout.css.animation-composition.enabled false true
layout.css.import-supports.enabled false true
layout.css.inline-style-caching.always-enabled undefined true
layout.css.named-pages.enabled true undefined
layout.css.nesting.enabled undefined false
layout.css.notify-of-unvisited true undefined
layout.css.properties-and-values.enabled undefined false
layout.css.scroll-anchoring.reset-heuristic-during-animation undefined false
layout.css.stylo-parallelism-threshold undefined 32
layout.css.stylo-threads undefined -1
layout.css.stylo-work-unit-size undefined 16
layout.dynamic-reflow-roots.enabled false true
media.aboutwebrtc.hist.closed_stats_to_retain undefined 8
media.aboutwebrtc.hist.enabled undefined false
media.aboutwebrtc.hist.poll_interval_ms undefined 250
media.aboutwebrtc.hist.prune_after_m undefined 2880
media.aboutwebrtc.hist.storage_window_s undefined 60
media.devices.enumerate.legacy.enabled undefined true
media.ffmpeg.allow-openh264 undefined true
media.gmp.decoder.reorder_frames undefined true
media.navigator.mediadatadecoder_vp8_hardware_enabled undefined false
media.videocontrols.picture-in-picture.respect-disablePictureInPicture undefined false
media.webrtc.platformencoder false true
media.webrtc.platformencoder.sw_mft false undefined
media.webrtc.platformencoder.sw_only undefined true
network.cache.frecency_array_check_enabled false true
network.cookie.sameSite.noneRequiresSecure false true
network.cors_preflight.authorization_covered_by_wildcard undefined true
network.early-hints.enabled false true
network.early-hints.preconnect.enabled false true
network.early-hints.preconnect.max_connections 0 10
network.http.http2.send-buffer-size 131072 0
network.jar.max_available_size undefined 268435456
network.jar.record_failure_reason false true
network.modulepreload undefined true
network.predictor.enable-prefetch false true
network.trr.odoh.configs_uri undefined
network.trr.odoh.enabled false undefined
network.trr.odoh.min_ttl 60 undefined
network.trr.odoh.proxy_uri undefined
network.trr.odoh.target_host undefined
network.trr.odoh.target_path undefined
network.wifi.scanning_period undefined 60000
places.frecency.pages.alternative.featureGate undefined false
places.frecency.pages.alternative.halfLifeDays undefined 30
places.frecency.pages.alternative.highWeight undefined 100
places.frecency.pages.alternative.lowWeight undefined 20
places.frecency.pages.alternative.mediumWeight undefined 50
places.frecency.pages.alternative.numSampledVisits undefined 10
plugin.state.flash 1 undefined
plugins.favorfallback.mode follow-ctp undefined
plugins.favorfallback.rules nosrc,video undefined
plugins.http_https_only true undefined
privacy.annotate_channels.strict_list.enabled false true
privacy.query_stripping.strip_on_share.enabled undefined false
security.block_fileuri_script_with_wrong_mime false true
security.disallow_non_local_systemprincipal_in_tests undefined false
security.remote_settings.crlite_filters.enabled false true
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
services.sync.prefs.sync.browser.offline-apps.notify true undefined
signon.firefoxRelay.privacy_policy_url undefined https://www.mozilla.org/%LOCALE%/privacy/subscription-services/
signon.firefoxRelay.terms_of_service_url undefined https://www.mozilla.org/%LOCALE%/about/legal/terms/subscription-services/
signon.signupDetection.enabled false true
svg.nearestAndFarthestViewportElement.enabled true false
toolkit.osfile.log false undefined
toolkit.telemetry.enabled false true
webgl.out-of-process.async-present.force-sync true false
widget.content.allow-gtk-dark-theme false undefined
widget.content.gtk-theme-override undefined
widget.gtk.non-native-menu-styling true undefined