public/

The public/ directory is used to serve your website’s static assets.

Files contained within the public/ directory are served at the root and are not modified by the build process. This is suitable for files that have to keep their names (e.g. robots.txt) or likely won’t change (e.g. favicon.ico).

public/
  favicon.ico
  og-image.png
  robots.txt

app/app.vue

<script setup lang="ts">
useSeoMeta({
  ogImage: '/og-image.png',
})
</script>

This is known as the static/ directory in Nuxt 2.