weapon_cubemap
weapon_cubemap is a weapon entity available in older Source engine games. It has been stripped out in games running on newer Source engine branches, such as Portal 2, Left 4 Dead 2 and Counter-Strike Global Offensive for an unknown reason. Though, a small mod has been made for Counter-Strike Global Offensive that restores it, made by TopHattWaffle and Zool Smith, which can be found here.
Entity description
This entity gives the player a set of spheres (models/shadertest/envballs.mdl), each with different reflective surfaces. It is used for checking cubemaps.
The commands to receive the weapon_cubemap (typed into the console) is either impulse 81 or give weapon_cubemap.
These commands are considered cheats, meaning that sv_cheats must be set to 1, or developer mode must be enabled, for them to work.
You can switch to this weapon (after having received it) by typing use weapon_cubemap.
Tip:To equip and draw the weapon for quick work, developers can bind this command to a specific key. For instance, typing bind "X" "impulse 81"; "use weapon_cubemap" will bind it to the X key. (You may need to press it twice the first time you use it in a map.)