In short
The technical specification is the contract annex defining, item by item, which materials and standards a building will be constructed to. In revenue-sharing contracts and off-plan sales it is the document that determines what you will actually receive at handover.
It covers every visible and invisible item in the building: floor coverings, door and window frames, thermal and acoustic insulation, plumbing materials, lifts, kitchen and bathroom fittings, facade cladding, shared areas and landscaping. For each item a brand, class or technical property is stated.
The most critical phrase in the document is "or equivalent". Once those two words appear beside a brand, in practice the seller decides what counts as equivalent at handover. If no lower bound is written for that equivalence, the specification loses its binding force even though it looks written down.
Why it matters to an investor
Almost all disputes at handover arise from items never written into the specification. Every unwritten item is left to the seller's preference, and that preference rarely lands where the buyer expected. This is the annex to read before the contract is signed.