I just browsed the text files of the game and I found some entries about FG42, flamethrower, and M4 Benelli (?!). Were these lines present in the disc version too?

Are they refering to some cut content, or maybe something else?

They were either already in original release, or in expansion pack release (I'm 90% sure patches added only working+released stuff).

They are referring to cut content, which didn't made it into release (IIRC some of this never got seriously into development, for example I can't recall a code for flamethrower was ever at least attempted, I believe it got removed just after trying out few particle effects, due to the visuals of flames not being on par with majority of game (did look gorgeous back then)... anyway, no regrets, if it would slip it in prototype, it would be removed later due to violence anyway (the torn-away-limbs got removed IIRC, they did exist at one stage of development)).

Damn, torn limbs? Is there any place where I could read or maybe see what was to be included at one point?

I kinda followed the game development back then through some czech PC gaming magazines, but it wasn't much. This is like my most favourite WW2 game ever, so I'd love to know more about it. :)

As far as I'm aware not. As with almost every enthusiastic software development, there were zillions of things tried and thrown away, it's sort of pity many players have no idea that what they actually see and get, even if it may look somewhat dumb or unfinished, is often already like 3rd-5th iteration, where the earlier version were even much worse... On the other hand it's sort of fair, to asses the quality of final thing, without nostalgic bias including the knowledge of effort spent over it.

If you like these stories, maybe you can try some mod development for some game, to get your own, it's even better than to read about others (although more exhausting, so I often just read about others too, instead of "writing" my own life).

Weird how there is stuff for a modern shotgun in the game files