The question of global_id field in ObjectId struct

[BlackHatChen]

Excuse me, About the discussion title, I want to know why the struct ObjectId in context.rs have one more id which called global_id if I activate the feature expose-ids?
And I'm not sure if we say "local" (contrary to global), does it mean "local context" (contrary to global context) or something else?

file: wgpu/src/context.rs
code:

/// Object id.
#[derive(Debug, Copy, Clone, PartialEq, Eq)]
pub struct ObjectId {
    /// ID that is unique at any given time
    id: Option<NonZeroU64>,
    **#[cfg(feature = "expose-ids")]**
    /// ID that is unique at all times
    **global_id: Option<crate::Id>**,
}