Leaving files alone: exclude

A file outside node_modules is a site module when its code mentions cssints (a name, a comment, cssints/plugin), with or without the attribute: that is how a forgotten attribute is found and told as an error. So the source of a plugin package, or of the engine, that a project bundles as code is also read as a site module, and fails (import { CSSStyleValue } from "cssints" is "without the attribute"). exclude names such files; the plugin does not transform, evaluate or drop them, in a build, on the dev server and in the private server of a build.

cssints({ exclude: ["**/packages/*/src/**", /\/vendor\//] });

• Vite's filter style. string | RegExp | ReadonlyArray<string | RegExp>, read as createFilter reads exclude: a picomatch glob (a relative one from the working directory) or a RegExp, matched on the module's file. There is no include: the rule of the attribute and of the mention already says which files are sites, and a list of the files to keep would only repeat it.
• Nothing changes without it. The default is no file excluded, so an app, a plugin package's own tests and the packages in node_modules behave as before, and a build pays one empty check per module. The attribute is not made the only marker: that would turn the forgotten-attribute error into a css that is undefined in the browser.
• An excluded file stays plain code. If it also carries with { type: "cssints" } imports, it is not evaluated either; exclude only files that are not sites.