For sales or distribution, the entire source code need to be made available to end users, including any code changes and additions—in that case, copyleft is applied to ensure that end users retain the freedoms defined above.
對於銷售或分銷，整個源代碼需要提供給最終用戶，包括任何代碼更改和添加 - 在這種情況下，應用copyleft來確保最終用戶保留上面定義的自由。