Stamina is a player statistics in Strife, which increases the maximum Health value and affects the damage computation in A_JabDagger. It starts at 0 and maxes at 100.
Stamina is increased by UpgradeStamina items which are granted at various points during the game.
It can be set for custom actors with the Stamina property, accessed from ACS with APROP_Stamina, and used in DECORATE expressions.
The alternate HUD will show the player's current accuracy and stamina if hud_showstats is true.