e.g. bootsect.exe. The file itself might have a slighly different
name, but inside it usually as a zip will be bootsect.exe itself.
Another I wasted hours trying to find MSNChatHook.dll
This could also be used to track the source of a strange file on your
computer so you could figure out what it was for.
Your spider does not need to download or unpack zip files, just
download the tail end plaintext index of file names at the end of the
zip file. Zip files are are usually fairly stable, so you would not
need to scan them very often.