The core idea
Central banks influence long-term yields through expected policy, asset purchases, communication and sometimes explicit yield targets, but long yields also reflect inflation, growth, supply and term premium.
What is happening underneath
Without a formal yield-curve-control regime, the long end remains a market-clearing price.
How investors should read it
Central-bank influence can be powerful without amounting to complete control.
The same market move can carry different information depending on which maturity, issuer and risk premium is changing. Read the question together with the underlying concepts rather than treating one price move as a universal signal.