Cargo Features

[dependencies]
aymr = { version = "0.0.1", default-features = false, features = ["btreemap", "hashmap", "sled_pre"] }
default = hashmap

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

btreemap
hashmap default
sled_pre = sled

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.

sled sled_pre?