Mafia 5. Seventeen Moments of Spring.

Your arguments are quite convincing, but I'll add something else to consider. :) Rift - his avatar is a picture from a Winnie the Pooh cartoon, isn't that a childish theme?! And also Hermit... Let's look at his profile:

Fight and seek, find and hide!..

The original is "Fight and seek, find and don't give up!" - This is the motto of the main character of the novel "Two Captains," Sanya Grigoriev - a Russian pilot. :) And now let's look at the inscription on the calendar page:

"You have a long way to go before you become Matrosov, you fascist beast!"

It's written in German, but it's clearly by a Russian. :) Next:

Don't put off until tomorrow what you can do the day after tomorrow!

This could indicate a "calendar page." And by the way, the material was a piece of a parachute dome. Parachutes are used by pilots. ;)

Added 1 minute ago
"Fight and seek, find and don't give up!" - :( I'm getting a 2 in Russian... :(