HTTPSLocalhost is built on top of devcert.
It's an electron app with added features that lets manage multiple local sites and runs a proxy for http and ws connections. It also gives you an easy to use ui, making it a better option than devcert.
HTTPSLocalhost adds a root signing authority to your system and uses that to generate new certificates. If you are worried about security of this approach, read security concerns.
Relevant parts of the source code are available openly for an audit.

