Cargo Features

[dependencies]
bevy_fixed_update_task = { version = "0.1.2", default-features = false, features = ["x11"] }
default = x11

The x11 feature is set by default whenever bevy_fixed_update_task is added without default-features = false somewhere in the dependency tree.

x11 default

Enables x11 of bevy

bevy:

X11 display server support

bevy_fixed_update_task has 2 features without comments.