Here is a list of all documented variables with links to the struct/union documentation for each field:

- p -

p : PixelColour, StringListReader
packet_queue : NetworkTCPSocketHandler
packet_recv : NetworkTCPSocketHandler
packets : CargoList< Tinst, Tcont >, PacketWriter
pad : LanguagePackHeader
padding : NWidgetBase, NWidgetPart::NWidgetPartUnion
page : StoryPageElement
pal : BridgeSpec, PalSpriteID, ParentSpriteToDraw
pal_identity : OpenGLSprite
pal_pbo : OpenGLSprite
pal_program : OpenGLBackend
pal_tex : OpenGLSprite
pal_texture : OpenGLBackend
palette : Blitter_32bppAnim, DropDownIcon< TBase, TEnd >, GraphicsSet, GRFConfig, Palette, TileLayoutRegisters, VideoDriver_CocoaQuartz
palette_remap : SpriteFile
palette_size : BmpInfo
palette_var10 : TileLayoutRegisters
pan_to_next : IntroGameViewportCommand
panel_widths : NWidgetScenarioToolbarContainer
param : GRFConfig
param_info : GRFConfig
param_nr : GRFParameterInfo
param_value : GRFError
parameter : DeterministicSpriteGroupAdjust
parameters : StringParameters
params : FoundTownWindow
parent : CargoDataEntry, FontCache, Group, NWidgetBase, Path, StringParameters, TileLayoutRegisters, Window
parent_button : DropdownWindow
parent_cls : WindowDesc
parent_scope : VehicleResolverObject
parent_sprites_to_sort : ViewportDrawer
part_of_subsidy : Industry, TownCache
participate_survey : NetworkSettings
partlists : GRFTownName
parts : NamePartList
passenger_capacity : AircraftVehicleInfo
password : NetworkAuthenticationDefaultPasswordProvider, NetworkAuthenticationPasswordRequestHandler
password_provider : X25519PAKEServerHandler
path : FileWriter, RoadVehicle, Ship
path_backoff_interval : PathfinderSettings
paths : LinkGraphJob::NodeAnnotation
pause_on_join : NetworkSettings
pause_on_newgame : GUISettings
payment : CargoDelivery
PAYMENT_GRAPH_X_STEP_DAYS : BaseGraphWindow
PAYMENT_GRAPH_X_STEP_SECONDS : BaseGraphWindow
peer_public_key : ServerNetworkGameSocketHandler, X25519AuthenticationHandler
performance : NetworkCompanyInfo
performance_history : CompanyEconomyEntry
period : BaseTimer< TTimerType >
periods : HistoryRange
periods_in_transit : CargoPacket
persist : DropdownWindow
persistent_buildingtools : GUISettings
persistent_mapping_supported : OpenGLBackend
pf : GameSettings
picker : WidgetDimensions
picker_title : RoadTypeInfo
picker_tooltip : RoadTypeInfo
pillar_flags : BridgeSpec
pip : NWidgetPart::NWidgetPartUnion
pip_inter : NWidgetPIPContainer
pip_post : NWidgetPIPContainer
pip_pre : NWidgetPIPContainer
pip_ratio_inter : NWidgetPIPContainer
pip_ratio_post : NWidgetPIPContainer
pip_ratio_pre : NWidgetPIPContainer
pitch : Blitter::BlitterParams
pixel_buffer : VideoDriver_CocoaQuartz
pixels : Textbuf
place_houses : EconomySettings
place_mode : TileHighlightData
plane_crashes : VehicleSettings
plane_speed : VehicleSettings
planned : LinkProperties
platforms : RailStationTileLayout
player_host_index : NetworkClientListWindow
player_self_index : NetworkClientListWindow
playing : MusicSettings
playlist : MusicSettings
playpos : MpsMachine::Channel
plugin_api : InternalSocialIntegrationPlugin
plugin_info : InternalSocialIntegrationPlugin
plural_count : PluralForm
plural_form : LanguageMap, LanguagePackHeader
population : HouseSpec, TownCache
population_in_label : GUISettings
pos : Aircraft, CursorSprite, CursorVars, Packet, RandomAccessFile, Scrollbar, TileHighlightData
pos_x : NWidgetBase
pos_y : NWidgetBase
position : AirportFTA, AirportFTAbuildup, AlternatingIterator< Titer >, DropdownWindow, ErrorMessageData, FaceVar, IntroGameViewportCommand, RailStationTileLayout::Iterator
position_consist_length : NewGRFCache
position_in_vehicle : NewGRFCache
position_same_id_length : NewGRFCache
positions : FallbackParagraphLayout::FallbackVisualRun, ICURun
post : NWidgetPartPIP
post_callback : IntSettingDesc, StringSettingDesc
pow_wag_power : RailVehicleInfo
pow_wag_weight : RailVehicleInfo
power : RailVehicleInfo, RoadVehicleInfo
powered_railtypes : RailTypeInfo
powered_roadtypes : RoadTypeInfo
pre_check : IntSettingDesc, StringSettingDesc
pref_height : WindowDesc
pref_sticky : WindowDesc
pref_width : WindowDesc
prefer_sprite : FontCacheSettings
prefer_teamchat : GUISettings
prefix : AutoCompletion, CurrencySpec
preset : NewGRFWindow
presetname_editbox : SavePresetWindow
presets : SavePresetWindow
president_name : CompanyNewsInformation, CompanyProperties
president_name_1 : CompanyProperties
president_name_2 : CompanyProperties
prev : HeaderFileWriter
prev_index : anonymous_namespace{framerate_gui.cpp}::PerformanceData
prev_storage : PersistentStorageArray< TYPE, SIZE >
preview_asked : Engine
PREVIEW_BOTTOM : PickerWindow
preview_company : Engine
preview_height : PickerCallbacks, PickerWindow
PREVIEW_HEIGHT : PickerWindow
PREVIEW_LEFT : PickerWindow
preview_sprite : AirportSpec, BuildAirportWindow
preview_wait : Engine
PREVIEW_WIDTH : PickerWindow
previous : Vehicle
previous_pos : Aircraft
previous_shared : Vehicle
price : BridgeSpec
price_base_multipliers : GRFFile
print_func : Squirrel
priority : DriverFactoryBase
prob : NamePart
probability : HouseSpec, IndustryTypeBuildData
proc : Button< T >, CheatEntry, GenWorldInfo, IConsoleCmd, OldChunks, QueryWindow
processing_time : HouseSpec
prod_level : Industry
produced : Industry
produced_cargo_filter_criteria : IndustryDirectoryWindow
produced_cargo_label : IndustrySpec
production : Industry::ProducedHistory, Town::SuppliedHistory
production_down_text : IndustrySpec
production_nobody : NewsSettings
production_offset_y : IndustryViewWindow
production_other : NewsSettings
production_player : NewsSettings
production_up_text : IndustrySpec
profit_last_year : GroupStatistics, Vehicle
profit_last_year_min_age : GroupStatistics
profit_this_year : Vehicle
programvelocities : MpsMachine
progress : Goal, Vehicle
proj : BaseGraphWindow::Filler< Tprojection >
prop : NIProperty
properties : NIFeature
prospecting_chance : IndustrySpec
psa : Airport, Industry
ptr : OldChunks
public_key : NetworkClientInfo