dredknight
when this patch was created i did not know what they mean, hence the name - unknown. Now I know - this is actually debuff maximum spell level the tent can clean per War Machine mastery.
0/0/1/3 means at none/basic/advanced/expert War Machines the tent will start removing debuffs of levels 1 and 3 at Advanced and Expert War Machine masteries.
First Aid Tent charges are stored somewhere in the xdb files in GameMechanics. You can increase it to any value you want.