That is a pretty recent policy, from the last year or two, it's available in a limited number of countries, and it's a pilot you need to manually apply for. And you still need to pay the fee to Google, it's only reduced by 4%, so instead of 30 it's 26 / instead of 15 it's 11.
More info: Google Play Help Center: Enrolling in the user choice billing pilot
If you're using the website, and if I understand you correctly, I believe the [ - ] button to the right of the comment author's username is what you're looking for.
Your universal link is missing the @instance part at the end, so it tries to redirect to a community called 'plugins' on the instance of whoever clicks on it.
This should work for everyone: /c/[email protected]
And if it doesn't, see the FAQ in the sidebar here; first search for https://sh.itjust.works/c/plugins on your instance so that it fetches info on the community, then you can click the above link again and it'll work.
I'm using Rust to build an alternative to https://amara.org (online collaborative subtitle editor). Initially I wrote the backend in node.js/typescript but I quickly found I really do not like working with that, and switched to Rust with Rocket. That has been really nice. I haven't gotten around to working on it for quite a long time though, would like to pick it up again this summer.
What's ml supposed to refer to? I tried looking it up but didn't find anything related to your message.
This was also the distribution I chose when first moving away from Windows and I can definitely recommend it. The vast majority of things worked out of the box, and people on the Linux Mint forum were very helpful in solving my remaining issues.
It's also possible to swap out the extension registry entirely and still use Microsoft's marketplace instead of Open VSX in VSCodium.