[pests]

In 2019 the CAs agreed not to issue certs to underscored subdomains making this less useful.

As evidenced by all your links being http.

(as an aside, it looks really weird seeing a bare http link in the wild - crazy that was the old norm!)

[tialaramex]

My browser is configured to auto-upgrade such links and I get a full screen interstitial when the upgrade fails (as of course it did for these)

This is now at a place where I'd recommend such configuration more broadly, it's not suitable for everybody, but many could benefit from just knowing all links are secured.

[jesprenj]

Wildcard certs match subdomains with underscores, as pointed out by a sibling comment. Example: https://_.4a.si./

[aaomidi]

A wildcard would still work for these fwiw