This works:
composer create-project symfony/skeleton:3.3.x-dev demo && \
cd demo && \
composer req twig && \
composer req profiler
But this fails:
composer create-project symfony/skeleton:3.3.x-dev demo && \
cd demo && \
composer req profiler

I'm not sure where/how to solve this.
There is another issue about this. The Symfony web profiler does not depend on the Twig bundle. When doing req twig, you install the Twig bundle. But not with the second example.
Not depending on TwigBundle but only on Twig was what made it possible to use WebProfilerBundle in Silex (which uses the bundle templates and controllers, but not the DI layer)
It seems there's a need for a specific composer pack for the web profiler that would require twig bundle too instead of relying just on symfony/web-profiler-bundle 馃槙
Quick thought: What about a WebProfilerBridge that contains all the code needed for Symfony and Silex? The bundle would then only be responsible for the DI part and could depend on TwigBundle.
For now (and to make it work on 3.3), I've created a profiler-pack. See symfony/recipes#77
Most helpful comment
Quick thought: What about a WebProfilerBridge that contains all the code needed for Symfony and Silex? The bundle would then only be responsible for the DI part and could depend on TwigBundle.