Via [url=https://steamcommunity.com/games/CSGO/announcements/detail/498332997840273410]the Steam Community[/url]:

[quote=Valve][b][u]GENESIS COLLECTION[/u][/b]
- The Genesis Collection is now available, featuring 17 finishes from community contributors.
- Access items in the Genesis Collection via the Genesis Uplink Terminal, available as a weekly drop.

[b][u]MAP SCRIPTING[/u][/b]
- Added cs_script, a JavaScript based scripting system for Counter-Strike maps.
- Added script_zoo.vmap to demonstrate cs_script usage and functionality.

[b][u]UI[/u][/b]
- Added ability to inspect another player's loadout when spectating.
- Added zoom (mousewheel) and pan (shift+drag) to all inspect panels.

[b][u]SOUND[/u][/b]
- Each grenade now has unique higher-fidelity sounds for draw, inspect, pin-pull, and throw.

[b][u]MISC[/u][/b]
- Various improvements to subtick shooting consistency.[/quote]

Rumor has it:

- Size is close to 3 GB - data capped users should take action now