Seriously - if you can attach a .capx then .c2addon should work as well - the way it is now it's annoying to either the maker, the users or both - you either rename the zip or put the renamed zip in a zip or put it up somewhere else where no download counts are present and the users can't be sure it will be available after a while.
Yeah, seriously, just do this. Tom
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For now attachments are taken down, but once the bug is fixed, this should be implemented in.
Keep your finger crossed Tom can fix the attachment bug, it's a mean one currently.