browser-sync cannot proxy https-websites - https

Question

I use browser-sync 2.11.1 with OS X Chrome 48.0.2564.97 (64-bit)
When I use it as a proxy for http-website:
browser-sync start --proxy http://example.com
it works great and I can point multiple browsers to localhost:3000 so that actions done in one of them are replicated in others.
However when I use it for https-website:
browser-sync start --proxy https://twitter.com
it doesn't work. When I point browsers to localhost:3000 they do not show up in "Current Connections" of browser-sync UI and also the actions are not replicated between them.
Maybe it has something to do with my browser complaining about https:
Is there a bug in browser-sync or am I missing something?

Answer 1

Apparently https://twitter.com is just a bad example. When I try https://about.gitlab.com/ the synchronization between my browsers does work:
browser-sync start --proxy https://about.gitlab.com/ --logLevel debug
According to the maintainer of browser-sync:
any large site like twitter has multiple techniques in place to
prevent proxing like this - and rightly so.
Browsersync is a development tool to be used on local addresses that
you're working on - in those cases it will work fine with HTTPS -
you'll just have to click accept on the warning about self-signed
certs :)

Answer 2

You might need to set https to true
browserSync({
proxy: "http://example.com/",
https: true
});
if that doesn't work try to append the https url to browserSync
browserSync.init({
socket: {
domain: "https://example.com" //with port if any => localhost:3000
},
proxy: 'http://example.com'
});

Answer 3

How to get secure gray lock icon in Chrome when using BrowserSync and xip.io and Wamp
First, generate .key and .crt files for localhost by running this in WSL or whatever you use for Bash:
cd /mnt/c/wamp64/certs/
openssl req -x509 -out localhost.crt -keyout localhost.key \
-newkey rsa:2048 -nodes -sha256 \
-subj '/CN=localhost' -extensions EXT -config <( \
printf "[dn]\nCN=localhost\n[req]\ndistinguished_name = dn\n[EXT]\nsubjectAltName=DNS:localhost\nkeyUsage=digitalSignature\nextendedKeyUsage=serverAuth")
Use PowerShell to tell Chome to trust that .crt file:
PS C:\wamp64\certs> certutil -addstore -enterprise -f "Root" .\localhost.crt
Completely exit Chrome (not just some tabs) by clicking ⋮ > Exit.
My BrowserSync options:
{
proxy: {
target: "https://myapp.192.168.1.113.xip.io" // Proxy an EXISTING vhost. Browsersync will wrap your vhost with a proxy URL to view your site.
},
host: "localhost", //the crt must have been created to match this (probably)
https: { //https://browsersync.io/docs/options/#option-https
key: "C:\\wamp64\\certs\\localhost.key",
cert: "C:\\wamp64\\certs\\localhost.crt"
},
port: 3000
}
Now https://localhost:3000/ works with a gray lock icon in the top left, as it should.