Via [url=https://steamcommunity.com/games/CSGO/announcements/detail/4213757668844649533]the Steam Community[/url]:

[quote=Valve][b][u]MISC[/u][/b]
- Fixed a visual bug where sniper rifle viewmodels could be visible at the edge of the scope screen overlay.
- Fixed a bug that prevented HE grenade explosions from breaking the vents in de_nuke.
- Fixed an issue where viewmodels would sometimes emit double shell eject effects.
- Minor performance improvements[/quote]

Rumor has it:

- Size is ~115 MB (with Workshop Tools installed)