A gray service envelope

"And when the adjutant left the scissor telescope for a quarter of an hour to conduct the necessary paperwork in the staff barracks, his eyes would more than once glance thoughtfully over the secret iron cupboard. Behind its door, hidden in a corner, lay a grey service envelope addressed to him in the commander's handwriting, sealed with the squadron's service seals. On 15 March, the Rittmeister had suddenly pressed this envelope into his adjutant's hand. ‘If I don't come back, open it.’ The commander also knew that this time it was going ‘to the very last and very extreme’. But that evening, the adjutant didn't need to open the squadron commander's will. Not yet."