Comment 4 for bug 201848

Yes. External modules are part of the orig.tar.gz .

I will quote part of Debian ChangeLog, where Patryk Cisek wrote about it:
"Kadu has a mechanism called "autodownload". It's purpose is to fetch
    external modules and themes (selected in .config file) by a configure
    script. This is unacceptable for Debian source package, because such data
    wouldn't be verifiable. external directory holds all these modules and
    themes and debian/extract.sh unpacks the tarballs, overriding autodownload
    mechanism."

BTW. Sorry for my English. It's not my native language ;)