همانطور که گفتین وقتی که یک repository اضافه می کنیم یک سری فایل رو دانلود میکنه که که طبق اطلاعات این ادرس داخل فایل pkgcache.bin ذخیره میشن که جاشم داخل
/var/cache/apt
هست
http://newbiedoc.sourceforge.net/system/apt-get-intro.html
to download, configure and install whichever packages you want. " Where does apt put all this stuff it downloads? The "cache" is located under /var/cache/apt/; there's a 'table-of-contents' file there called pkgcache.bin (and if you're set up to also get source-code packages, you'll also have srcpkgcache.bin) and the actual *.deb package files are in /var/cache/apt/archives/. "
البته شک دارم هنوز جوابم کاملا درست باشه