Preview of the proposed up-rust native-frame-model branch (up-rust b6b99c6d, up-spec f0e9b17) — not released documentation. branch · write-up
up_rust::frame::codec

Constant FIELD_PERMISSION_LEVEL

Source 
pub const FIELD_PERMISSION_LEVEL: u32 = _; // 16u32
Expand description

Presence bit: the frame has a permission level.