What problem does this feature solve?

Vue compiler prefixes all identifiers used in template syntax with this or _ctx except these:

https://github.com/vuejs/vue-next/blob/master/packages/shared/src/globalsWhitelist.ts

Is there a way that we can add some custom globals like window , or __MY_GLOBAL_CONSTANT__ to globals? If we could, then we can use env variables (or ...) directly and it makes tree-shaking works inside render-tree.

I encountered this problem here

https://github.com/SasanFarrokh/vite-plugin-multi-device#caveats

What does the proposed API look like?

inside vueCompilerOptions add another field to extend the globalsWhitelist like

vueCompilerOptions: {
   globalsWhitelist: ['window', '__DEVICE__']
}

I ran into this trying to use console.log() inside a template. You get an absolutely bizarre-sounding error:

Uncaught TypeError: Cannot read properties of undefined (reading 'log')

Unless you think to disable sourcemap support, you have no idea that it's rewriting console.log to _ctx.console.log, and even then it's not easy to find this issue.