Refactor data for better readability

**Problem**
When working with core, the error messages could be more descriptive.

**Suggestion**
Improve error handling and add detailed error messages.

**Context**
This would help with debugging and maintenance.

Start by locating the core error-handling code and reading how current error messages are produced. Identify the cases covered by the issue before deciding on changes. Done means error messages are more descriptive and the relevant behavior is verified.

Written by the indexing model from the issue text.