Enriching original email: This is about whether packages transmission-gtk should use embedded copy of libb64 or depend on the outdated Debian package libb64.
Upstream for libb64 seems dead and transmission devs have improved their embedded/vendored copy of libb64. Direct link: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=1073005 First question: Are the libb64 improvements by Transmission devs generic, could they be copied as patches to the Debian libb64 package for everyone's benefit?