Via [url=http://blog.counter-strike.net/index.php/2018/10/21333/]the CS:GO blog[/url]:

[quote=Valve][GAMEPLAY]
– Adjusted the start-of-half economy with the goal of reducing the impact of a pistol round win on subsequent rounds.
— In Competitive Matchmaking, both teams are now considered to start the half with a one-round ‘losing streak’ that is reset following a round win. Instead of $1400, the Round 1 loser receives $1900, then $2400 for a subsequent loss, etc.
— The start-of-half losing streak can be adjusted via “mp_starting_losses”

– CZ75a: Adjusted the CZ75a to encourage semi-automatic fire at medium and long ranges.
— increased recoil and fire inaccuracy
— slightly improved accuracy recovery rate

– Tec9: Adjustments to make the weapon more forgiving at medium rates of fire.
— reduced fire inaccuracy
— slightly improved accuracy recovery rate

– SG553 price reduced to $2750
– AUG price reduced to $3150

[MAPS]
– Austria is now available in Competitive Matchmaking.
– Austria has been moved into Group Delta in official Casual matchmaking.
– [b]New Community maps Biome and Subzero are now available in Casual matchmaking as part of Group Sigma.[/b]
– Canals has been removed from Competitive Matchmaking.
– Shipped and Insertion are no longer available in official matchmaking.

[AUDIO]
– Added a “VOIP Positional” audio setting. When this setting is enabled, in-game voice audio will be played from the position the player is standing at.

[MISC]
– Enabled mouse bindings for voice chat to work in end of match scoreboard.
– Fixed backlog of async events in scoreboard causing performance problems during gameplay.[/quote]

Rumor has it:

- Script changes and additions for Biome and Subzero, as well as your usual dose of localization and a couple of protobuf changes: https://github.com/SteamDatabase/GameTracking-CSGO/commit/02c444ff7e57f14f6c2879e33d95f383c3c360fa
- Otherwise what you see described above is pretty much what you're getting, a large majority of the size is for all the map pool shuffling

- Size is ~200 MB