: These are "highly compressed" versions (sometimes as small as a few GBs) hosted on external sites. Caution is advised with these, as they are not official and often come with security risks. Legitimate Ways to Reduce TF2's File Size

Сообщество Steam :: Руководство :: How to optimize TF2

If you are looking to save space or improve performance on a lower-end PC, there are safer alternatives to downloading sketchy compressed installers.

: Community-created maps often use bzip2 compression to speed up download times for players joining custom servers.

: Using tools like the CompactGUI on GitHub to compress the game's existing files without affecting gameplay performance.