I've been doing a lot of XML editing to quickly copy things like conditional formatting in dashboards. I find it helpful to use XML comments to mark my place and note beginning and ends of logical areas of work.
All is well, the re-zipped files upload fine and the updated dashboards work as expected.
However, when I export again later, my comments are gone. ( 4.9.7 - so this may be different in more recent versions? )
I'd like for them to not be.
** I've only tested this w/ exported dashboard XML, the benefit of persisting comments would apply to schema and business schema as well.