Well, 'Gundam War in the Pocket Novel' might be about the struggles and battles within the Gundam universe. Gundam has a vast array of different mobile suits, each with their own capabilities. In this novel, it may show how these mobile suits are deployed in war, the strategies used by the different factions. It might also introduce new characters or expand on the backstories of existing ones, all within the context of a war - torn Gundam - filled world.
I'm not entirely sure as I haven't read it specifically. But generally, a 'war in the pocket' novel might be about small - scale battles or conflicts that occur in a confined area or among a small group of people during a war.
Since I don't know the specific 'war in the pocket novel', I can't say for sure. But usually, there could be soldiers, like a young and inexperienced private who has to grow up fast in the chaos of war.
There were many war cartoons like Gundam Seed:
1 Legend of Galaxy Heroes
2." Mech Suit Gundam 08, Team Ms "
3. Gate of the Fate Stone
Death Note
5. Crown of Sin
6. The Attacking Giant
7 Naruto
8 Sword and Sword God Domain
9 《Fate/Zero》
[10: Metal Alchemist]
These cartoons all involved war and combat elements, but also had profound philosophical and psychological descriptions.
One of the main events was the initial Zeon surprise attack on the Earth Federation. Another is the discovery and deployment of the Gundam by the Federation. There were also many space battles around key colonies.