Valve introduced Terminals as part of Counter-Strike 2's 'Show Off' update. Terminals are part of the Genesis Collection, which includes a total of 17 items, and can sometimes be obtained via weekly drops. Alternatively, of course, they can be purchased through the Steam Market.
The arms dealer NPC you're connected with when you access a Genesis Terminal will begin to showcase weapon skins, one at a time. You can either say yes, or say no, and you can keep saying no up to four more times, at which point the Genesis Terminal is no longer accessible.
Genesis Terminals can be opened for free. Nice! Wait, opening it is free, but isn't this is all, in effect, still a lootbox? You're gambling on the odds that something nice will pop up. You'll experience FOMO if you decline something in the hopes of something else, which turns out to be an inferior item. You're also forced to pay for whichever item you do choose, and depending on its quality, you're looking at $1,587 USD for an M4A4 | Full Throttle in 'Factory New' condition.
YouTuber MrMaxim has assembled a great overview trailer above, which goes into greater detail on Genesis Terminals, and it's pretty clear what Valve is probably doing here. By altering the core lootbox mechanic such that players are kind of, sort of, but only barely, given control of their prospective purchases, they likely seek to circumvent regulations in countries with stern anti-lootbox policies.
And, oh. Look. Spotted on ResetEra, Valve has proudly proclaimed that customers can now unseal Genesis Terminal items in Belgium, The Netherlands, and France. That's grand! The French government takes umbrage with lootboxes that contain real-world currency offerings; meanwhile, both Belgium and The Netherlands are sternly committed to a full-scale ban on the practice.
The M4A4 | Full Throttle is available on the Steam Market for $526, but it's listed under the 'Minimal Wear' category. If you want it 'Factory New', as best as I can tell, that's dang near sixteen hundred bucks. The Genesis Collection seems like an experiment on Valve's part; if successful, they might well start nixing the Cases mechanic, which is unequivocally a lootbox.