Governments putting backdoors on telecom infrastructures, isn't that done for decades?
FYI, Chinese government has mandated all browsers, freeware or not, sold and provided download in China, to have built in HTTPS root CA CNNIC, which is governed by a Chinese government affiliated hosting provider.
That means, whenever you connect to any website physically in China without a VPN, Chinese government can intercept the connection, change the CA provider to CNNIC, and use a compromised certificate to trick your browser. In the whole process, your browser will think it's been connected to a genuine root CA certified server.
Then, they will start an HTTPS client to your ultimate server and fetch data for you. In this process, they have access to the date without encryption, so they can spy on you or tamper with your data without you knowing anything went wrong, unless you are careful enough to check CA provider every time, or just disable CCNIC, which is a bad idea in China because many genuine Chinese websites are signed by CNNIC.