I think they meant in terms of design. It does look strikingly like the layout and design of plausible.
It has similarities but to be fair Plausible is also very close to the stock Tailwind UI components: https://tailwindui.com
Yes Plausible using tailwind and I'm using Bulma because I'm comfortable in it. I like plausible and I have chosen their design language for GAClient. And I don't think anything wrong with it. I'm not cloning Plausible but creating add-on for Google Analytics in the same design as Plausible.
"Design language"? It looks like a bad rip-off.
Actually, Fathom.
Ha ha! No lol. Actually Fathom is totally different from Plausible. I don't like Fathom way to showing metrics so I reverse engineered ( so many people are saying cloned ) the plausible frontend.