It doubles/triples/quadruples amount of gained ammo packs during certain hours.
Default: from 18h to 24h. Can be changed with cvars.
Default multiplier: 2x
Cvars:
zp_hhstart < number > - time when to start happy hours
zp_hhend < number > - time when to end happy hours
zp_hhx < number > - how many times to multiply happy hour rewards