It happens to me sometimes: creating a new field, and entering the field name too late. Or by copying a field, it gets a default slug like single_line_text-2. As slugs are used in code in automations, it is better to have slugs that really show what the field is about.
I haven’t found a way to correct a slug, other than deleting the field and creating a new one. It would be nice if it were possible to change the slug somehow.