No, zero means a 0% expense ratio and no minimums, as listed for the four funds at the top of https://www.fidelity.com/mutual-funds/investing-ideas/index-.... Unlike most other funds, these are captive to Fidelity so if you ever do an ACATS transfer they have to be liquidated.
It's an interesting reversal and highlights the power of competition - as a young part-time employee in college, my employer automatically contributed a few hundred dollars for me to a 403(b) type of retirement savings account. Fidelity was the custodian and after I left the job, it imposed a substantial monthly fee that eventually ate all of the money in the account, leaving me with zero. I always remember that episode when dealing with Fidelity.
In taxable it could cause you to have to stay with Fidelity or eat a tax bill.