I found the GitHub for it: https://github.com/StractOrg/stract/tree/main

What I still can't figure out (in my very shallow dive into the repo) is if it's a meta search engine like Searx-ng or if it does its own crawling and builds its own search index.

I run Searx-ng and love it, but I'd be interested in a true self-hosted search (though I'd need to devote a lot of resources to build and run such an index).

Anyone know?

Update: Looks like it crawls and maintains its own index. From the credits/thanks at the bottom of the readme (emphases mine):

The commoncrawl organization for crawling the web and making the dataset readily available. Even though we have our own crawler now, commoncrawl has been a huge help in the early stages of development.