ability to export CSV data
Not sure that an "issue" is the right way to track this or not. Late last year, I added some code to an older version of this extension to allow me to export CSV data that I could then put into a spreadsheet. I intended to try and keep it in sync with the core code and eventually submit it back. Sadly, life intervened, and I haven't had the chance to keep it up (though I'm still actively using that fork). The code is at <https://bitbucket.org/dmose/hgactivity/wiki/Home>, and you're more than welcome to bring it up to date and incorporate it into the core, if you're so inclined.
It may be that the divergence is now great enough that it won't be interesting for the core, in which case I won't be in the slightest bit offended. :-)