Cargo Features

[dependencies]
percent-encoding-rfc3986 = { version = "0.1.3", default-features = false, features = ["std", "alloc"] }
default = alloc

The alloc feature is set by default whenever percent-encoding-rfc3986 is added without default-features = false somewhere in the dependency tree.

std = alloc
alloc default std?

percent_encoding_rfc3986 has 3 features without comments.