The extension refers to archives created by the open-source 7-Zip software . It is widely favored in technical communities for its superior compression ratios, often reducing file sizes by 20% to 40% more than standard ZIP formats.
Even after converting a file to .3ds , you face limitations. The 3DS format is ancient (1988). Any reputable repack should warn you, but they don't. Here is the truth: 7z to 3ds converter repack