Via [url=https://steamcommunity.com/games/CSGO/announcements/detail/687522235410284762]the Steam Community[/url]:

[quote=Valve][b][u]ANIMATION[/u][/b]
- Fixed some cases of popping and glitching when switching weapons and reloading at extreme angles

[b][u]MISC[/u][/b]
- Fixed bot pathing issue in Retakes game mode
- Fixed a rendering hang on DX11
- Improved avx / avx512 instruction set detection
- Miscellaneous stability and performance improvements[/quote]

Rumor has it:

- Size is ~1 GB (with Workshop Tools installed)