Localized Environment Variables Based On siteUrl?
I also set up those two environment variables (totally custom variables, with the one specialty that they are passed to the CP)
for my multilibgual sites.

But I have both basePath and baseUrl combined for all my locales!

'.dev' =&gt; array(
    'siteUrl' =&gt; array(
        'en' =&gt; 'http://local.mysite.dev/',
        'fr' =&gt; 'http://local.mysite.dev/fr/',
    ),
    'environmentVariables' =&gt; array(
        'basePath' =&gt; '/path-to-mysite/public/',
        'baseUrl' =&gt; 'http://local.mysite.dev/',
    )
)


I use these variables for two things:


Make assets from local asset sources available to all my locales. I set them absolutely, because relative paths don't
do it in this case, as the path to the assets' folder and the URL is a different one from http://example.com/fr/ as it is from http://example.com/.
Build absolute URLs to static files from my templates, e.g.
&lt;link rel="stylesheet" href="{{ craft.config.environmentVariables.baseUrl }}stylesheets/site.css" /&gt;
Both, the url() function and the siteUrl variable don't work in this case, they always return the site's URL including the locale part.


So it's basically just a way to build absolute URLs to Craft assets and files for me.

I'm actually not totally sure how much of this could be solved with root relative paths, but in my case I've also
at least one environment where the path from web root to the craft site is differently to my other environments.

(For testing sites on mobile devices where I can't set virtual domains, I have an environment to access the site via the
local machine's IP address. As there's multiple sites on that machine, they are all in subfolders under web root.)