This is the 3MHz aviation band, so it cannot be legal for free banders.
Russians and Ukrainians use them very much in the evenings, calling them "TROIKA".
The band starts at around 2900 where USB works, and above 3 MHz only AM. As ID they use popular words such as: pike, captain, dynamo,budilnik, priboj.
They sometimes play music, e.g. the station Brittany from Odessa UA, Mirage from Tambov.
They exchange reports and technical notes, sometimes one of them organizes a "collective".
They do not talk about politics or provide contact details - they only invite people to communicate via radio.
They use "home-made" ones called "scharmanka" or high-power military surplus transmitters - ugly, wide modulation, imprecise tuning, unstable carrier.
Sometimes some of them emit a very strong second harmonic, heard by me at about 6.3 MHz in the "European" band of the Free station.