Via [url=https://steamcommunity.com/games/CSGO/announcements/detail/717913919982667305]the Steam Community[/url]:

[quote=Valve][b][u]MAP SCRIPTING[/u][/b]
- Added custom_hud_layout entity
- custom_hud_layouts are the entry point for scripted maps to provide custom UI.
- Panel, Label, Image, and Button panel types are supported.
- Styling with css is supported.
- Events and client side scripting are not supported.
- Maintains state during tools mode reloads.

- Added cs_player_camera entity
- Gives control of a player's view without moving their pawn
- Can be configured to let the player look around from the scripted position

- Added Instance.Delay
- Added Instance.OnBombPlantStart
- Added Instance.OnBombPlantAbort
- Added Instance.OnBombDefuseStart
- Added Instance.OnBombDefuseAbort
- Added Instance.OnCustomHudClicked
- Added Instance.IsDedicatedServer
- Added Entity.Move
- Added Entity.GetMoveType
- Added Entity.SetMoveType
- Added CSPlayerPawn.GetC4
- Added CSPlayerPawn.GetDefuseTarget
- Added CSPlayerPawn.IsBuyMenuOpen
- Added CSPlayerPawn.GetCamera
- Added C4.GetPlantStartTime
- Added C4.GetPlantFinishTime
- Added C4.AbortPlant
- Added CustomHudLayout.SetHasClass
- Added CustomHudLayout.SetHasClassForPlayer
- Added CustomHudLayout.SetDialogVariableString
- Added CustomHudLayout.SetDialogVariableStringForPlayer
- Added CustomHudLayout.SetInputCaptureEnabled
- Added CustomHudLayout.IsInputCaptureEnabled
- Added CSPlayerCamera.IsEnabled
- Added CSPlayerCamera.SetEnabled
- Added CSPlayerCamera.SetIsControllingAngles
- Added enum CSMoveType
- Corrected types for some events where parameters were maybe undefined.
- Errors encountered during initial script run are now logged to the console.
- Unhandled promise rejections are now logged to the console.
- Added the column number to errors caught during the CompileModule step of script loading.
- Deprecated planter from Instance.OnBombPlant event
- Deprecated defuser from Instance.OnBombDefuse event[/quote]

Rumor has it:

- Size is close to 150 MB (with Workshop Tools installed)