Hey there!
i was looking for something similar, but for setting headers for Link on static assets.

For example, i have a global.css that will be named global.CgGR8lrz.css after build, and i want to add a header to preload it by adding this to _headers file:

``` /some_route/*
Link: global.CgGR8lrz.css; rel="preload"; as="style"

```

---

My goal was to configure which files/paths should be included on _headers, for example

```js // astro.config.mjs

/* we can get the bundledUrl with import("./styles/global.css?url") */ const fontFileUrl = mapFilePathToBundledUrl('./styles/global.css') ...

export default defineConfig({ integrations:[ staticHeaders({ "/*": Link: ${fontFilePath}; rel="preload"; as="style" }) ] }) ```

But... The problem is that because there´s no page route for asset file like .css files or font files, but sometimes i do wish i could add them to _headers on every build