Ren'Py reserves filenames that are do not begin with a letter or number, and filenames that begin with "00". Very specifically, filenames that start with "00" and "_" are used by Ren'Py internally.
Ren'Py reserves all names beginning with a single underscore (_). Do not use names beginning with an underscore, as that may cause your game to break in future versions of Ren'Py.
The following is a list of names that are used by Python. Re-using these names can lead to obscure problems.
The following is a list of names that are used by Ren'Py. While in some cases it makes sense to redefine these names, one should be aware that doing so can cause obscure problems.
AddToSet()
AlphaBlend()
AlphaDissolve()
AlphaMask()
AnimatedValue()
At()
Attribute()
AudioData()
AudioPositionValue()
BarValue
Borders()
BrightnessMatrix()
Call()
CaptureFocus()
Character()
ClearFocus()
Color
ColorizeMatrix()
ComposeTransition()
Composite()
Condition()
ConditionSwitch()
Confirm()
ContrastMatrix()
Crop()
CropMove()
DictInputValue()
DictValue()
DisableAllInputValues()
Dissolve()
Drag
DragGroup
DynamicDisplayable()
DynamicImage()
EndReplay()
Fade()
FieldInputValue()
FieldValue()
FileAction()
FileCurrentPage()
FileCurrentScreenshot()
FileDelete()
FileJson()
FileLoad()
FileLoadable()
FileNewest()
FilePage()
FilePageName()
FilePageNameInputValue()
FilePageNext()
FilePagePrevious()
FileSave()
FileSaveName()
FileScreenshot()
FileSlotName()
FileTakeScreenshot()
FileTime()
FileUsedSlots()
Fixed()
Flatten()
FontGroup()
Frame()
Function()
Gallery
GamepadCalibrate()
GamepadExists()
GetCharacterVolume()
GetFocusRect()
GetTooltip()
Grid()
HBox()
Help()
Hide()
HideInterface()
HueMatrix()
IdentityMatrix()
If()
Image()
ImageDissolve()
InputValue
InvertMatrix()
InvertSelected()
Jump()
Language()
LayeredImage()
LayeredImageProxy()
Live2D()
MainMenu()
Matrix()
MixerValue()
Model
MouseDisplayable()
MouseMove()
MoveTransition()
Movie()
MultiPersistent
MultipleTransition()
MusicRoom
NoRollback
Notify()
Null()
NullAction()
OffsetMatrix()
OpacityMatrix()
OpenDirectory()
OpenURL()
ParameterizedText()
Pause()
PauseAudio()
Pixellate()
Placeholder()
PlayCharacterVoice()
Preference()
PushMove()
Queue()
QueueEvent()
QuickLoad()
QuickSave()
Quit()
RemoveFromSet()
Replay()
RestartStatement()
Return()
RollForward()
Rollback()
RollbackToIdentifier()
RotateMatrix()
SaturationMatrix()
ScaleMatrix()
ScreenVariableInputValue()
ScreenVariableValue()
Screenshot()
Scroll()
SelectedIf()
SensitiveIf()
SepiaMatrix()
SetCharacterVolume()
SetDict()
SetField()
SetLocalVariable()
SetMixer()
SetMute()
SetScreenVariable()
SetVariable()
SetVoiceMute()
Show()
ShowMenu()
ShowTransient()
ShowingSwitch()
SideImage()
Skip()
SlottedNoRollback
SnowBlossom()
Solid()
Sprite
SpriteManager
Start()
StaticValue()
Style
StylePreference()
Swing()
Text()
Tile()
TintMatrix()
ToggleDict()
ToggleField()
ToggleFocus()
ToggleLocalVariable()
ToggleMute()
ToggleScreen()
ToggleScreenVariable()
ToggleSetMembership()
ToggleVariable()
ToggleVoiceMute()
Tooltip
Transform
VBox()
VariableInputValue()
VariableValue()
VoiceReplay()
With()
XScrollValue()
YScrollValue()
adv
alt
blinds
center
dissolve
ease
fade
hpunch
irisin
left
main_menu
menu
mouse_visible
move
moveinright
moveoutright
name_only
narrator
nvl_clear()
nvl_hide()
nvl_menu()
nvl_show()
offscreenleft
offscreenright
pixellate
pushright
reset
right
save_name
say
slideawayleft
slideleft
squares
topleft
topright
truecenter
voice()
voice_can_replay()
voice_replay()
voice_sustain()
vpunch
wipeleft
zoomin
zoominout
zoomout