Here is a DNS capture of a fresh Firefox install
detectportal.firefox.com.
location.services.mozilla.com.
locprod1-elb-eu-west-1.prod.mozaws.net.
mozilla.org.
www.mozilla.org.
firefox.settings.services.mozilla.com.
d2k03kvdk5cku0.cloudfront.net.
ocsp.digicert.com.
cs9.wac.phicdn.net.
incoming.telemetry.mozilla.org.
pipeline-incoming-prod-elb-149169523.us-west-2.elb.amazonaws.com.
search.services.mozilla.com.
spocs.getpocket.com.
getpocket.cdn.mozilla.net.
proxyserverecs-1736642167.us-east-1.elb.amazonaws.com.
search.r53-2.services.mozilla.com.
ocsp.sca1b.amazontrust.com.
push.services.mozilla.com.
autopush.prod.mozaws.net.
content-signature-2.cdn.mozilla.net.
d2nxq2uap88usk.cloudfront.net.
img-getpocket.cdn.mozilla.net.
shavar.services.mozilla.com.
shavar.prod.mozaws.net.
firefox-settings-attachments.cdn.mozilla.net.
d80i88epwmv41.cloudfront.net.
tracking-protection.cdn.mozilla.net.
d1zkz3k4cclnv6.cloudfront.net.
snippets.cdn.mozilla.net.
d228z91au11ukj.cloudfront.net.
accounts.firefox.com.
getpocket.com.
slate.com.
www.nextadvisor.com.
www.gq.com.
jezebel.com.
fe2.edge.pantheon.io.
www.theguardian.com.
condenast.map.fastly.net.
dualstack.guardian.map.fastly.net.
www.youtube.com.
www.facebook.com.
www.reddit.com.
youtube-ui.l.google.com.
www.wikipedia.org.
star-mini.c10r.facebook.com.
twitter.com.
reddit.map.fastly.net.
dyna.wikimedia.org.
www.vox.com.
www.washingtonpost.com.
medium.com.
vox-chorus.map.fastly.net.
e9631.j.akamaiedge.net.
www.joinhoney.com.
landing.chirpbooks.com.
www.reviewed.com.
joinhoney.com.
secure.pageserve.co.
domains.gannett.map.fastly.net.
www.google.com.
ocsp.pki.goog.
pki-goog.l.google.com.
www.netmeister.org.
panix.netmeister.org.
incoming.telemetry.mozilla.org
Brave fresh install DNS capture:
updates.bravesoftware.com.
f2.shared.global.fastly.net.
static1.brave.com.
no-thanks.invalid.
no-thanks.invalid.cable.rcn.com.
laptop-updates.brave.com.
no-thanks.invalid.
go-updater.brave.com.
componentupdater.brave.com.
brave-core-ext.s3.brave.com.
tor.bravesoftware.com.
crlsets.brave.com.
no-thanks.invalid.
no-thanks.invalid.cable.rcn.com.
krdjdubihfhlri.cable.rcn.com.
rhqnzult.cable.rcn.com.
ckzlqdialux.cable.rcn.com.
krdjdubihfhlri.cable.rcn.com.
krdjdubihfhlri.
rhqnzult.cable.rcn.com.
ckzlqdialux.cable.rcn.com.
rhqnzult.
ckzlqdialux.
rhqnzult.
ckzlqdialux.
no-thanks.invalid.
no-thanks.invalid.cable.rcn.com.
static.brave.com.
no-thanks.invalid.
no-thanks.invalid.cable.rcn.com.
SOURCE:
https://www.netmeister.org/blog/browser-startup.html