Backpack

The backpack is a feature that gives a player the ability to use tools. This is one of the starting features that have existed since 2006. The backpack can be also used for scripting. There are also hotkeys that exist, numbered from 0 to 9.

Assets
There are 4 lua assets/corescripts which were used to build the backpack from 2011 to 2014

BackpackBuilder (14th of June, 2011 - 14th of August, 2014)

BackpackResizer (14th of June, 2011 - 14th of November, 2012)

BackpackGear (3rd of August, 2012 - 24th of July, 2014)

BackpackManager (3rd of August, 2012 - 14th of August, 2014)

2006–2009
The backpack in 2006 was very simplistic. This backpack could carry up to 10 tools; if a player had too many tools, they would begin to disappear. The only way to get those extra tools was to get rid of 3D tools by pressing backspace.

2009–2011
When gear was introduced in May 2009, Roblox administrators updated it so that a player could have up to around 30 gears, or tools. It is similar to the old backpack, in which extra tools would disappear.

2011–2012
Around the fall of 2011, the backpack was updated, which allowed the player to access any tools beyond 30. However, it was possible for the backpack to break, and make the tools inaccessible. The backpack also contained a search bar, which could search up any relative tool name. The backpack button was located near the player's health bar.

2012–2015
The backpack used from 2012 to 2015 is the same as the previous one, but when closing the backpack, the close button may not have appeared. To access the backpack, the player would've needed to click the arrow pointing up.

2015–2016
It is the same as the previous one, but the arrow pointing up is on the top left corner, with a backpack icon instead of an arrow.

2016–present
The current backpack has no arrow, and features transparent squares for each gear. Up to 10 gears can be shown on the main HUD.