Cargo Features

Deq has no features set by default.

[dependencies]
deq = { version = "0.2.1", features = ["serde_skip_history"] }
serde_skip_history = serde

Features from optional dependencies

In crates that don't use the dep: syntax, optional dependencies automatically become Cargo features. These features may have been created by mistake, and this functionality may be removed in the future.

serde serde_skip_history?