Rebellion has released several free and paid DLC weapon packs (like the Mosin-Nagant and Kar98) and three major DLC missions (Kraken Awakes, etc.). Repacks rarely get updated. You are stuck with the Day 1 patch forever.
Repack groups—such as FitGirl, DODI, or ElAmigos—take the original game files (often from a scene release or a legitimate copy) and apply extreme compression. For Sniper Elite 5, this can shrink the download from 80GB down to 25GB–35GB. The trade-off? The user must decompress the files during installation, which can take 30 minutes to over an hour depending on your CPU and hard drive speed. sniper elite 5 repack
This is the big one. While some repack groups are "trusted" in the piracy scene, you are downloading executable files (.exe) from random websites. It is incredibly common for fake repacks to contain: Rebellion has released several free and paid DLC