Firefox
Running firefox as user-
[user@dom0 ~]$ qvm-run -a fedora-34-dvm firefox-esr
about:config
app.normandy.enabled - false
app.normandy.first_run - false
app.normandy.api_url - blank
beacon.enabled - false
media.peerconnection.enabled - false
media.peerconnection.use_document_iceservers - false
media.eme.enabled = false
media.navigator.enabled = false
browser.cache.disk.enable = false
browser.cache.offline.enable = false
browser.cache.disk.capacity = 0
browser.cache.offline.capacity = 0
browser.send_pings - false
browser.send_pings.require_same_host - true
browser.search.geoSpecificDefaults - false
browser.search.geoSpecificDefaults.url - (blank)
browser.search.geoip.url - (blank)
browser.urlbar.speculativeConnect.enabled - false
privacy.donottrackheader.enabled - true
privacy.donottrackheader.value - 1
privacy.trackingprotection.enabled - true
privacy.resistFingerprinting = true
privacy.trackingprotection.fingerprinting.enabled = true
privacy.trackingprotection.cryptomining.enabled = true
privacy.firstparty.isolate = true
geo.enabled - false
geo.wifi.uri - (blank)
geo.provider.network.url - blank
toolkit.telemetry.enabled - false
toolkit.telemetry.server - (blank)
webgl.disabled - true
dom.event.clipboardevents.enabled = false
dom.ipc.plugins.flash.subprocess.crashreporter.enabled = false
dom.battery.enabled - false
network.dns.disablePrefetch - true
network.prefetch-next - false
network.dns.disableIPv6 - true
network.cookie.cookieBehavior = 4
network.cookie.lifetimePolicy = 2
network.security.esni.enabled = true
network.http.speculative-parallel-limit = 0
network.captive-portal-service.enabled - false
network.IDN_show_punycode - true
captivedetect.canonicalURL - blank
layout.css.visited_links_enabled - false
device.sensors.enabled - false
dom.security.https_only_mode = true
dom.security.https_only_mode_ever_enabled = true
Optional
network.trr.mode = 3
network.trr.custom_uri = https://dns.nextdns.io/xxxxxx (replace with your ID)
network.trr.resolver = https://dns.nextdns.io/xxxxxx
about:preferences
Check following and Do as following if required
Disable Play DRM controlled Content
Change HomePage and NewTabs to Blank
Disable every Entry of Firefox Home Content
Change Default search engine to Searx private instance if you don't have any then to Qwant.
Disable Search Suggestions
Set Enahanced Tracking Protection to Strict.
Set Do not track Parameter to Always
Set to Delete Cookies and Site Data to clean when Firefox Closes.
Disable Logins and Password Storage
Set Firefox not to Remember History.
Set Address Bar to suggest nothing.
Disable Every entry in Firefox Data collection and Telemetry.
Check settings in DNS over https.
Privacy & Security > Permissions > Block location, microphone etc.
Add-ons
ublock origin, Decentraleyes