X_CORE_THROWER_UNCALLED
Means
a @ultimat3/core export that throws a coded error has no non-test caller
Typical cause
a refusal nobody receives — assertEnvExample was one, deleted in 25.0.0; it reads as protection and protects nothing
Fix
bun run scripts/declaration-readers-callers.ts --json # after deleting it, calling it, or pinning it as app-facing API with its caller