Cargo Features

openssh = { version = "0.10.3", default-features = false, features = ["process-mux", "native-mux"] }
default = process-mux

The process-mux feature is set by default whenever openssh is added without default-features = false somewhere in the dependency tree.

process-mux default
native-mux = openssh-mux-client

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.

openssh-mux-client native-mux?