pub const BUILTIN_SIGN_COLUMNS: [&str; 2];Expand description
The built-in gutter columns, left to right (SG.4a).
The host owns the ORDER (a gutter whose columns moved per buffer would be unreadable) but nothing about what goes in each one — that is entirely the registry’s answer. Making this list user-configurable is the obvious next step and is deliberately not taken here: it changes the gutter’s WIDTH, which every scroll, wrap and cursor-column calculation reads.