I'm maintaining a tool in debian that installs package.el packages so
they can be managed by the system package system.
For various reasons (see http://reproducible-builds.org for motivations)
it is desirable if packages unpack into elpa directories in a
reproducible (i.e. bit identical every time) way. Unfortunately
update-directory-autoloads uses (current-time), which effectively means
this unpacking is different every time. It would be nice to be able to
override the time used, or perhaps eliminate the timestamp entirely.