Volt is template engine for Phalcon Framework and it is very similar to twig. At the moment PhpStorm doesn't support .volt templates and these files are unreadable.

If volt is similar to twig then you can enable reading .volt files as .twig.

Easy way to better world ;-)

Come on to File > Settings > Editor > File Types, and find Twig in "Recognize file types", and in "registered patterns" add new pattern "*.volt". Save it.

Happy codding ;-)