explain or xref "with a clock"

[royfielding]

Section 10.2.2

A recipient with a clock that receives a response message without a
[...]
A recipient with a clock that receives a response with an invalid

Are we using "with a clock" as shorthand for "have a clock capable of
providing a reasonable approximation of the current instant in
Coordinated Universal Time"? It might be worth clarifying if this
different phrasing than above is intended to convey different semantics.