I'm using WXT as the boilerplate. It has nothing to do with ESLint and it doesn't come with any ESLint dependencies or configurations.

Install the dependencies and then run the lint script with whatever package manager you are using. You'll see that ESLint detects the type parameters in the Svelte component against the no-undef rule.

I'm not sure if this on the plugin to solve or the user has to hack around their own ESLint configuration file.