In plain English
FAR 52.227-23, Rights to Proposal Data (Technical), is a contract clause prescribed at FAR 27.409(l), most recently dated June 1987. The complete official text is reproduced below, verbatim, from GSA's published FAR source files.
Its text contains no sentence requiring insertion into subcontracts; see the flowdown section below for what that does and does not mean.
Does it flow down to subcontracts?
No flowdown mandate found in the clause text
We scanned the full clause text and found no sentence directing the contractor to insert this clause into subcontracts. That is a statement about the text, not legal advice: a prime contractor may still flow terms down contractually, an agency supplement (DFARS, VAAR, …) may add requirements, and clauses listed below (if any) may order this clause into subcontracts from the outside.
Where it's prescribed
As prescribed in 27.409(l), insert the following clause:
Prescribing reference: FAR 27.409(l).
The official text, verbatim
As prescribed in 27.409(l), insert the following clause:
Rights to Proposal Data (Technical) (June 1987)
Except for data contained on pages _____, it is agreed that as a condition of award of this contract, and notwithstanding the conditions of any notice appearing thereon, the Government shall have unlimited rights (as defined in the "Rights in Data-General" clause contained in this contract) in and to the technical data contained in the proposal dated ____________, upon which this contract is based.
(End of clause)