Firefox user.js config based on https://www.privacy-handbuch.de/download/moderat/user.js.

user.js

// Mozilla User Preferences
// Privacy-Handbuch, moderate user.js (vom 21.03.2020)
// Download: https://www.privacy-handbuch.de/handbuch_21u.htm

user_pref("_user.js.prhdb", "moderat_21032020");

user_pref("app.normandy.enabled", false);
user_pref("app.normandy.api_url", "");
user_pref("app.shield.optoutstudies.enabled", false);
user_pref("browser.aboutHomeSnippets.updateUrl", "");
user_pref("browser.cache.compression_level", 1);
user_pref("browser.cache.disk.enable", false);
user_pref("browser.cache.disk_cache_ssl", false);
user_pref("browser.cache.offline.enable", false);
//user_pref("browser.display.use_document_fonts", 0); // https://www.privacy-handbuch.de/handbuch_21d2.htm sowie https://www.privacy-handbuch.de/handbuch_21q.htm zuviele Seiten werden falsch angezeigt ohne Fonts
user_pref("browser.fixup.alternate.enabled", false);
user_pref("browser.formfill.enable", false);
user_pref("browser.link.open_newwindow.restriction", 0);
user_pref("browser.library.activity-stream.enabled", false);
user_pref("browser.newtabpage.activity-stream.enabled", false);
//user_pref("browser.newtabpage.enabled", false); // https://www.privacy-handbuch.de/handbuch_21d5.htm neue Tab Seite aktiv lassen
user_pref("browser.newtabpage.activity-stream.asrouterExperimentEnabled", false);
user_pref("browser.newtabpage.activity-stream.asrouter.userprefs.cfr.addons", false);
user_pref("browser.newtabpage.activity-stream.asrouter.userprefs.cfr.features", false);
user_pref("browser.newtabpage.activity-stream.telemetry", false);
user_pref("browser.newtabpage.activity-stream.feeds.sections", false);
user_pref("browser.newtabpage.activity-stream.feeds.snippets", false);
user_pref("browser.newtabpage.activity-stream.feeds.telemetry", false);
user_pref("browser.newtabpage.activity-stream.feeds.systemtick", false);
user_pref("browser.newtabpage.activity-stream.feeds.topsites", false);
user_pref("browser.newtabpage.activity-stream.feeds.section.topstories.options", "");
user_pref("browser.newtabpage.activity-stream.telemetry.ping.endpoint", "");
user_pref("browser.onboarding.enabled", false);
user_pref("browser.pagethumbnails.capturing_disabled", true);
user_pref("browser.ping-centre.telemetry", false);
user_pref("browser.ping-centre.production.endpoint", "");
user_pref("browser.ping-centre.staging.endpoint", "");
user_pref("browser.privatebrowsing.autostart", false);
user_pref("browser.safebrowsing.downloads.remote.url", " ");
user_pref("browser.safebrowsing.downloads.enabled", false);
user_pref("browser.safebrowsing.phishing.enabled", false);
user_pref("browser.safebrowsing.malware.enabled", false);
user_pref("browser.safebrowsing.downloads.remote.enabled", false);
user_pref("browser.safebrowsing.downloads.remote.block_dangerous", false);
user_pref("browser.safebrowsing.downloads.remote.block_dangerous_host", false);
user_pref("browser.safebrowsing.downloads.remote.block_potentially_unwanted", false);
user_pref("browser.safebrowsing.downloads.remote.block_uncommon", false);
user_pref("browser.safebrowsing.blockedURIs.enabled", false);
user_pref("browser.safebrowsing.provider.google.gethashURL", "");
user_pref("browser.safebrowsing.provider.google.updateURL", "");
user_pref("browser.safebrowsing.provider.google4.gethashURL", "");
user_pref("browser.safebrowsing.provider.google4.updateURL", "");
user_pref("browser.safebrowsing.provider.mozilla.gethashURL", "");
user_pref("browser.safebrowsing.provider.mozilla.updateURL", "");
user_pref("browser.search.update", false);
user_pref("browser.search.geoSpecificDefaults", false);
user_pref("browser.search.geoSpecificDefaults.url", "");
user_pref("browser.search.geoip.url", "");
user_pref("browser.search.suggest.enabled", false);
user_pref("browser.search.reset.enabled", false);
user_pref("browser.search.reset.whitelist", "");
user_pref("browser.sessionstore.max_tabs_undo", 0);
user_pref("browser.sessionstore.max_windows_undo", 0);
user_pref("browser.sessionstore.privacy_level", 2);
user_pref("browser.slowStartup.notificationDisabled", true);
user_pref("browser.slowStartup.maxSamples", 0);
user_pref("browser.slowStartup.samples", 0);
//user_pref("browser.startup.page", 0); // https://www.privacy-handbuch.de/handbuch_21d5.htm Startseite aktiv lassen
user_pref("browser.tabs.crashReporting.sendReport", false);
user_pref("browser.urlbar.speculativeConnect.enabled", false);
user_pref("browser.urlbar.trimURLs", false);
user_pref("browser.urlbar.oneOffSearches", false);
user_pref("browser.urlbar.suggest.openpage", false);
user_pref("browser.urlbar.suggest.searches", false);
user_pref("camera.control.face_detection.enabled", false);
user_pref("camera.control.autofocus_moving_callback.enabled", false);
user_pref("datareporting.healthreport.uploadEnabled", false);
user_pref("datareporting.policy.dataSubmissionEnabled", false);
user_pref("devtools.webide.autoinstallADBHelper", false);
user_pref("devtools.webide.enabled", false);
user_pref("device.sensors.enabled", false);
//user_pref("dom.enable_performance", false); linkedin.com funktioniert nicht
user_pref("dom.enable_performance_navigation_timing", false);
user_pref("dom.enable_resource_timing", false);
user_pref("dom.gamepad.enabled", false);
user_pref("dom.webnotifications.enabled", false);
user_pref("extensions.blocklist.enabled", false);
user_pref("extensions.blocklist.url", "");
user_pref("extensions.getAddons.cache.enabled", false);
user_pref("extensions.htmlaboutaddons.discover.enabled", false);
user_pref("extensions.htmlaboutaddons.recommendations.enabled", false);
user_pref("extensions.ui.lastCategory", "addons://list/extension");
user_pref("extensions.formautofill.addresses.enabled", false);
user_pref("extensions.formautofill.creditCards.enabled", false);
user_pref("extensions.formautofill.heuristics.enabled", false);
user_pref("extensions.pocket.enabled", false);
user_pref("extensions.screenshots.disabled", true);
user_pref("extensions.screenshots.upload-disabled", true);
user_pref("extensions.systemAddon.update.enabled", false);
user_pref("extensions.systemAddon.update.url", "");
user_pref("extensions.webextensions.restrictedDomains", "");
user_pref("font.blacklist.underline_offset", "");
user_pref("layers.acceleration.disabled", true);
user_pref("media.cache_size", 0);
user_pref("media.eme.enabled", false);
user_pref("media.navigator.enabled", false);
user_pref("media.navigator.video.enabled", false);
user_pref("media.peerconnection.enabled", false);
user_pref("media.video_stats.enabled", false);
user_pref("media.webspeech.synth.enabled", false);
user_pref("network.allow-experiments", false);
user_pref("network.dns.disablePrefetch", true);
user_pref("network.dns.disableIPv6", true);
user_pref("network.captive-portal-service.enabled", false);
user_pref("network.connectivity-service.enabled", false);
user_pref("network.http.altsvc.enabled", false);
user_pref("network.http.altsvc.oe", false);
//user_pref("network.http.referer.XOriginPolicy", 2); // icloud.com funktioniert nicht, stattdessen Addon Smart Referer verwenden
user_pref("network.http.speculative-parallel-limit", 0);
user_pref("network.IDN_show_punycode", true);
user_pref("network.manage-offline-status", false);
user_pref("offline-apps.allow_by_default", false);
user_pref("offline-apps.quota.warn", 0);
user_pref("places.history.enabled", false);
user_pref("plugin.default.state", 0);
user_pref("plugins.enumerable_names", "");
user_pref("plugins.update.url", "");
user_pref("privacy.clearOnShutdown.cache", true);
user_pref("privacy.clearOnShutdown.cookies", true);
user_pref("privacy.clearOnShutdown.downloads", true);
user_pref("privacy.clearOnShutdown.history", true);
user_pref("privacy.clearOnShutdown.offlineApps", true);
user_pref("privacy.clearOnShutdown.openWindows", false);
user_pref("privacy.clearOnShutdown.sessions", true);
user_pref("privacy.clearOnShutdown.formdata", true);
user_pref("privacy.clearOnShutdown.siteSettings", true);
user_pref("privacy.cpd.offlineApps", true);
user_pref("privacy.cpd.passwords", true);
user_pref("privacy.cpd.siteSettings", true);
user_pref("privacy.donottrackheader.enabled", false);
user_pref("privacy.firstparty.isolate", true);
user_pref("privacy.firstparty.isolate.block_post_message", true);
user_pref("privacy.history.custom", true);
user_pref("privacy.resistFingerprinting.block_mozAddonManager", true);
user_pref("privacy.sanitize.migrateClearSavedPwdsOnExit", true);
user_pref("privacy.sanitize.sanitizeOnShutdown", true);
user_pref("privacy.userContext.enabled", true);
user_pref("privacy.userContext.ui.enabled", true);
user_pref("privacy.userContext.longPressBehavior", 2);
user_pref("privacy.usercontext.about_newtab_segregation.enabled", true);
user_pref("reader.parse-on-load.enabled", false);
user_pref("security.cert_pinning.enforcement_level", 2);
user_pref("security.family_safety.mode", 0);
user_pref("security.identityblock.show_extended_validation", true);
user_pref("security.insecure_connection_icon.enabled", true);
user_pref("security.insecure_connection_icon.pbmode.enabled", true);
user_pref("security.insecure_connection_text.enabled", true);
user_pref("security.insecure_connection_text.pbmode.enabled", true);
user_pref("security.mixed_content.upgrade_display_content", true);
user_pref("security.mixed_content.block_active_content", true);
user_pref("security.secure_connection_icon_color_gray", false);
user_pref("security.ssl.require_safe_negotiation", true);
user_pref("security.ssl.treat_unsafe_negotiation_as_broken", true);
user_pref("signon.autofillForms", false);
user_pref("signon.formlessCapture.enabled", false);
user_pref("startup.homepage_welcome_url", "");
user_pref("toolkit.coverage.endpoint.base", "");
user_pref("toolkit.coverage.opt-out", true);
user_pref("toolkit.telemetry.archive.enabled", false);
user_pref("toolkit.telemetry.coverage.opt-out", true);
user_pref("toolkit.telemetry.bhrPing.enabled", false);
user_pref("toolkit.telemetry.firstShutdownPing.enabled", false);
user_pref("toolkit.telemetry.hybridContent.enabled", false);
user_pref("toolkit.telemetry.newProfilePing.enabled", false);
user_pref("toolkit.telemetry.shutdownPingSender.enabled", false);
user_pref("toolkit.telemetry.updatePing.enabled", false);
user_pref("toolkit.telemetry.server", "");
user_pref("toolkit.telemetry.unified", false);
user_pref("toolkit.telemetry.infoURL", "");
user_pref("ui.use_standins_for_native_colors", true);
//user_pref("ui.systemUsesDarkTheme", 0); // Firefox dark mode funktioniert nicht mehr
user_pref("webgl.disable-extensions", true);
user_pref("webgl.disable-fail-if-major-performance-caveat", true);
user_pref("webgl.min_capability_mode", true);
user_pref("webgl.enable-debug-renderer-info", false);

user_pref("network.trr.resolvers", '[{ "name": "Cloudflare", "url": "https://mozilla.cloudflare-dns.com/dns-query" },{ "name": "NextDNS", "url": "https://trr.dns.nextdns.io/" },{ "name": "SecureDNS", "url": "https://doh.securedns.eu/dns-query" },{ "name": "AppliedPrivacy", "url": "https://doh.appliedprivacy.net/query" },{ "name": "Digitale Gesellschaft (CH)", "url": "https://dns.digitale-gesellschaft.ch/dns-query" }, { "name": "Freifunk Muenchen", "url": "https://doh.ffmuc.net" }, { "name": "Quad9", "url": "https://dns.quad9.net/dns-query" }]'); 

// eigene Änderungen
user_pref("browser.newtabpage.activity-stream.feeds.section.highlights", false); // https://www.privacy-handbuch.de/handbuch_21d5.htm
user_pref("browser.discovery.enabled", false);
user_pref("browser.search.openintab", true);
user_pref("browser.startup.homepage", "about:home");
// <-- https://www.privacy-handbuch.de/handbuch_21n.htm
user_pref("browser.startup.homepage_override.mstone", "ignore");
user_pref("startup.homepage_welcome_url.additional", "");
user_pref("startup.homepage_override_url", "");
// -->
user_pref("browser.tabs.warnOnClose", false);
user_pref("browser.urlbar.openintab", true);
// <-- theme
user_pref("extensions.activeThemeID", "firefox-compact-dark@mozilla.org");
user_pref("devtools.theme", "dark");
// -->
user_pref("signon.rememberSignons", false);
// <-- Adressleiste zurücksetzen
user_pref("browser.urlbar.update1", false);
// -->

user_pref("_user.js.prhdb", "SUCCESS");