Repack installers often trigger "False Positives" in antivirus software. It is common practice to temporarily disable your AV during installation or add the folder to your exclusions.
FitGirl is a well-known group that compresses large game files into smaller installers. This makes them easier to download for users with slower internet or limited data caps.
Typically includes several language options; you can often "selective download" only the ones you need to save space.