The Freedom Fighters is a cut Terrorist faction added in February 17, 2016 Update to Counter-Strike: Global Offensive files.
References to faction was added in February 17, 2016 Update (Operation Wildfire) along with wearables to game files.
In August 18, 2016 update, all text references mentioning wearables with faction was removed from
They description says:
"A mysterious faction with unclear and potentially violent motive. While ostensibly claiming a cause of freedom, these fighters are nonetheless heavily armed."