Some brokerages break down various types of position (equity, bond, etc). Mine in particular has a "Cash and equivalents" section. Money market accounts go there, but so do treasury funds and such.

I suspect the upvotes are because you're technically correct, treasuries are not literally cash. The downvotes are because grandparent obviously meant that treasuries are considered cash equivalents (whether or not they actually should be, given liquidity concerns).

Treasuries (without further qualification) are not cash equivalents. (And it’s not because of liquidity concerns.)

Treasury bills may be cash equivalents. They present (almost) no interest risk.

Long-term treasury notes/bonds is what was being discussed. There is interest risk in that case and neither your broker nor anyone else would consider them cash equivalents (unless they are already close to maturity).