To determine the essential component commonly included in a construction tender document, we need to understand what each option represents concerning construction documentation:

1. Project drawings prepared without technical specifications:
   • While project drawings are crucial in a tender document, they should ideally be accompanied by technical specifications to detail the precise requirements of construction. Drawings alone, without these specifications, are not typically sufficient for a comprehensive tender document.
2. Technical specifications describing project requirements:
   • This is a crucial component in construction tender documents. Technical specifications provide detailed information about the materials, workmanship, and quality standards necessary to complete the project per the client's requirements. They help ensure that all bidders have the same understanding of what is required and can provide accurate project cost estimates and timelines. Without these, the tender document would be incomplete.
3. Promotional brochures issued for project advertisement:
   • While promotional brochures can be part of marketing and advertisement strategies, they do not form a technical or essential component of a construction tender document.
4. Financial records of all participating contractors:
   • The financial records of contractors are usually not part of the tender document itself. Instead, contractors typically submit their financial records as part of their bid to demonstrate their financial capability to undertake the contract.

Based on the explanations above, we conclude that technical specifications describing project requirements are the essential component commonly included in a construction tender document. These specifications play a critical role in outlining the detailed aspects of the project needed for accurate bidding and execution.