alt Hacker NewsIt clearly shows in the example that @r translated to "site:www.reddit.com" in their resulting search- I did not read "supporting domain search in general" as being Kagi specific.
The Kagi specific part is /easily/ searching a site in Kagi.
The whole point here is that they are extending the already supported bangs[1] to search the domain with "@", thus if "!r" exists to redirect to Reddit's search, you can use @r to search Reddit within Kagi.
Of course I could type "site:Reddit.com" that's what I've been doing for years, including on Kagi, but easily doing that with @<bang> seems exclusive to Kagi.
[1] Kagi maintains an open source list of supported bangs here, you can even do a PR to add even more: https://github.com/kagisearch/bangs
My concern was not with the ability to do the "site-specific search", but the bullshit regarding this feature to be "exclusive" to Kagi.
If you're saying a different syntax makes something exclusive, I have some highly non-performant macros to sell you.