You can find the settings.cfg file located in left4dead2/ems/survivorperks/ of your main L4D2 directory. You can reload the setting file ingame at any time by typing '!reloadperkconfig' in the chat box.

The settings are as follows:

usevslib - Default(1) If 1, the perks requiring VSlib are enabled

allowincoop - Default(1) If 1, the perks are enabled in campaign mode
allowinsurvival - Default(1) If 1, the perks are enabled in survival mode
allowinversus - Default(1) If 1, the perks are enabled in versus mode
allowinscavenge - Default(1) If 1, the perks are enabled in scavenge mode

nick_givedeagle - Default(1) If 1, Nick starts with a Deagle
nick_ffres - Default(0.5) The damage multiplier for Nick's friendly fire resistance
nick_usealtperk - Default(0) If 1, Nick uses an alternative perk where he gains temporary HP from killing special infected(automatically enabled is usevslib is 0)
nick_altperk_hp - Default(8) The temporary HP Nick gains from killing a special if using his alt perk

ro_useoldperk - Default(0) If 1, Rochelle uses her old higher max HP perk
ro_oldperk_maxhp - Default(110) Rochelle's default maximum health

coach_useoldperk - Default(0) If 1, Coach uses his old higher bash damage perk
coach_givebat - Default(1) If 1, Coach starts with a baseball bat
coach_oldperk_shovedamagemin - Default(50) Coach's minimum damage against commons when bashing
coach_oldperk_shovedamagemax - Default(60) Coach's maximum damage against commons when bashing
coach_oldperk_shovedamageplymin - Default(70) Coach's minimum damage against specials when bashing
coach_oldperk_shovedamageplymax - Default(80) Coach's maximum damage against specials when bashing

ellis_giveshotgun - Default(1) If 1, Ellis starts with a wooden shotgun
ellis_shotgunammo - Default(24) The default ammo of Ellis' starting shotgun
ellis_reloadmult - Default(1.12) The multiplier for Ellis' reload speed

bill_useoldperk - Default(0) If 1, Bill uses his old faster reload with rifles perk
bill_oldperk_reloadmult - Default(1.25) The multiplier for Bill's rifle reload speed
bill_oldperk_allowak - Default(1) If 1, Bill reloads the AK47 faster as well
bill_firemult - Default(1.2) The multipler for Bill's firing speed with non-automatic weapons

zoey_givepistol - Default(1) If 1, Zoey starts with dual pistols
zoey_movemult - Default(1.1) The multiplier for Zoey's movement speed

louis_givebomb - Default(1) If 1, Louis starts with a pipe bomb
louis_pillshpext - Default(15) The extra HP Louis gets from pills on top of the default 50
louis_reloadmult - Default(1.15) The multiplier for Louis’ rifle reload speed
louis_allowak - Default(1) If 1, Louis reloads the AK47 faster as well

francis_damageres - Default(0.9) The multiplier for Francis' damage resistance
francis_usealtperk - Default(0) If 1, Francis uses an alternative perk where he has infinite shoves(automatically enabled is usevslib is 0)