> tencent.com returns an empty reply for me at the moment

That's because the correct address is https://www.tencent.com/ (prefixed with www.)

Wow. Can the massive chinese conglomerate really not forward that to www?

They are hardly the only site to do that. It is only by convention that non-www-prefixed websites tend to redirect to www-prefixed one. It's not at all mandatory and technically they are two different hostnames. It may be intentional to ensure only exactly the right hostnames are ever used, e.g., www, ftp, smtp, etc.

Rather unusual, but it’s a corporate rather than customer-facing website so not really all that important. It’s not like apple.com, google.com, or microsoft.com where the brand name domain is the product or is where the products are sold. I just checked and apex domains for all their flagship products redirect to www just fine.

Seems to be working as intended, it's a non www url.

I rarely see a site that doesn't redirect it to the appropriate subdomain. Then again I don't often check it unless it's broken

Oh, nice catch! Strange setup.