Cargo Features

[dependencies]
v8 = { version = "0.91.0", default-features = false, features = ["use_custom_libcxx"] }
default = use_custom_libcxx

The use_custom_libcxx feature is set by default whenever v8 is added without default-features = false somewhere in the dependency tree.

use_custom_libcxx default

V8 has 2 features without comments.