Constant FS_SYNC_FROM_PTY 

pub const FS_SYNC_FROM_PTY: u16 = _; // 16u16

Resolve the sync’s base directory from a pty’s live cwd: a trailing [src_pty_id:2] names a pty and the server joins path onto its cwd (docs/ide.md Decision 3). It comes last, after any EXCLUDE field.