The original intention for the “Create Archive” button was exactly that - to be able to gather all the pieces (including the TeX macros, source SFM files, fonts, illustrations, and so on) in order for the exact same output to be produced in another location, at a (much) later time, and even on different hardware (with a different OS). Our experience over the last couple of years is that it is easy to miss one crucial file which potentially scuttles the whole process (for example we recently discovered that the AdjLists were being missed, so they have since been added). So, right now we’re erring on the side of caution and possibly including more than we need to, but for good reason.
I believe that SourceCodePro-Light.ttf has been included as a small font to handle the identification text around the edge of the page when cropmarks are printed. The other fonts are VERY important as they inevitably change over time, and you only need a minor change to a standard font like Charis SIL for the whole job to break, or require reflowing/balancing the text.
You are probably right that the .XDV file isn’t needed for a true long-term publication archive, but it is sometimes helpful in the case of a troubleshooting archive.
So I would suggest that if size is an issue (for upload reasons), that you carefully weed out any files from the .ZIP that you feel are superfluous before uploading. But be careful not to make any wrong assumptions.
There is an issue out there (enhancement request #499) regarding the automatic creation of an archive for submission to REAP. That’s where we’d like to be eventually, but the discussion is progressing rather slowly.
