This is difference between the default preference of Firefox 109.0 beta 3 and one of 108.0.1. This diff table is generated with my small script firefox-prefjs-surveyer.

Preference difference
PrefFirefox 108.0Firefox 109.0 beta 3
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
apz.scrollend-event.content.enabled false true
browser.cache.offline.enable true false
browser.migrate.content-modal.enabled undefined false
browser.migrate.opera-gx.enabled undefined false
browser.migrate.showBookmarksToolbarAfterMigration true undefined
browser.migrate.vivaldi.enabled undefined false
browser.newtabpage.activity-stream.asrouter.providers.cfr {"id":"cfr","enabled":true,"type":"remote-settings","bucket":"cfr","updateCycleInMs":3600000} {"id":"cfr","enabled":true,"type":"remote-settings","collection":"cfr","updateCycleInMs":3600000}
browser.newtabpage.activity-stream.asrouter.providers.message-groups {"id":"message-groups","enabled":true,"type":"remote-settings","bucket":"message-groups","updateCycleInMs":3600000} {"id":"message-groups","enabled":true,"type":"remote-settings","collection":"message-groups","updateCycleInMs":3600000}
browser.newtabpage.activity-stream.asrouter.providers.whats-new-panel {"id":"whats-new-panel","enabled":true,"type":"remote-settings","bucket":"whats-new-panel","updateCycleInMs":3600000} {"id":"whats-new-panel","enabled":true,"type":"remote-settings","collection":"whats-new-panel","updateCycleInMs":3600000}
browser.newtabpage.activity-stream.telemetry.ut.events false true
browser.opaqueResponseBlocking.syntheticBrowsingContext false true
browser.opaqueResponseBlocking.syntheticBrowsingContext.filter false true
browser.pdfjs.feature-tour {"screen":"FEATURE_CALLOUT_1","complete":false} {"screen":"","complete":false}
browser.places.snapshots.relevancy.timeOfDayIntervalSeconds undefined 3600
browser.places.snapshots.score.CurrentSession undefined 1
browser.places.snapshots.score.IsUserPersisted undefined 1
browser.places.snapshots.score.IsUserRemoved undefined -10
browser.places.snapshots.score.Visit undefined 1
browser.places.snapshots.source.CommonReferrer undefined 3
browser.places.snapshots.source.Overlapping undefined 3
browser.places.snapshots.source.TimeOfDay undefined 3
browser.snapshots.relevancy.timeOfDayIntervalSeconds 3600 undefined
browser.snapshots.score.CurrentSession 1 undefined
browser.snapshots.score.IsUserPersisted 1 undefined
browser.snapshots.score.IsUserRemoved -10 undefined
browser.snapshots.score.Visit 1 undefined
browser.snapshots.source.CommonReferrer 3 undefined
browser.snapshots.source.Overlapping 3 undefined
browser.snapshots.source.TimeOfDay 3 undefined
browser.urlbar.contextualSearch.enabled undefined false
browser.urlbar.quickactions.enabled undefined true
browser.urlbar.quickactions.showInZeroPrefix undefined false
browser.urlbar.quickactions.showPrefs undefined true
browser.urlbar.resultMenu undefined false
browser.urlbar.searchEngagementTelemetry.enabled undefined false
browser.urlbar.shortcuts.quickactions undefined true
browser.urlbar.suggest.quickactions undefined true
devtools.remote.adb.extensionURL https://ftp.mozilla.org/pub/mozilla.org/labs/devtools/adb-extension/#OS#/adb-extension-latest-#OS#.xpi https://ftp.mozilla.org/pub/labs/devtools/adb-extension/#OS#/adb-extension-latest-#OS#.xpi
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.forms.always_allow_pointer_events.enabled undefined false
dom.mozTextStyle.enabled undefined false
dom.range_element.magnet_effect_threshold undefined 10.0
dom.security.credentialmanagement.identity.wait_for_timeout true undefined
dom.webidl.crosscontext_hasinstance.enabled true false
extensions.InstallTrigger.enabled true false
extensions.install_origins.enabled undefined false
extensions.manifestV3.enabled false true
extensions.unifiedExtensions.enabled false true
extensions.webapi.testing undefined false
extensions.webapi.testing.http undefined false
extensions.webcompat-reporter.enabled false true
extensions.webextensions.default-content-security-policy.v3 script-src 'self'; script-src 'self'; upgrade-insecure-requests;
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.canvas.accelerated.aa-stroke.enabled undefined true
gfx.canvas.accelerated.gpu-path-complexity undefined 4000
gfx.canvas.accelerated.stroke-to-fill-path undefined false
gfx.direct2d.target-independent-rasterization.disabled undefined false
html5.inert.enabled false true
javascript.options.mem.gc_parallel_marking undefined false
javascript.options.mem.gc_small_heap_incremental_limit 140 150
layout.css.allow-mixed-page-sizes undefined false
layout.css.content-visibility-relevant-content-margin undefined 50.0
layout.css.mod-rem.enabled undefined false
layout.dynamic-reflow-roots.enabled false true
media.seamless-looping-video false true
media.webrtc.platformencoder.sw_mft false true
network.cache.frecency_array_check_enabled false true
network.cookie.sameSite.laxByDefault false true
network.cookie.sameSite.laxByDefault.allowBoomerangRedirect undefined true
network.cookie.sameSite.noneRequiresSecure false true
network.jar.record_failure_reason false true
network.predictor.enable-prefetch false true
network.ssl_tokens_cache_use_only_once false true
network.webtransport.datagrams.enabled undefined false
network.webtransport.enabled undefined false
print.print_via_parent true undefined
privacy.annotate_channels.strict_list.enabled false true
privacy.partition.always_partition_third_party_non_cookie_storage false true
privacy.partition.always_partition_third_party_non_cookie_storage.exempt_sessionstorage true false
privacy.resistFingerprinting.block_mozAddonManager 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
svg.nearestAndFarthestViewportElement.enabled undefined false
toolkit.telemetry.dap_helper https://helper1.dap.cloudflareresearch.com/v01 https://helper1.dap.cloudflareresearch.com/v02
toolkit.telemetry.dap_leader https://interop-00.api.divviup.org https://dap-02.api.divviup.org
toolkit.telemetry.dap_task1_enabled undefined false
toolkit.telemetry.enabled false true
toolkit.telemetry.shutdownPingSender.backgroundtask.enabled undefined false
webgl.out-of-process.async-present false true