When I download a content product via DIM it downloads two files - a ZIP and a DSX each with the same filename (e.g. 'IM00030698-01_UltraGenesis23.dsx' and 'IM00030698-01_UltraGenesis23.zip'), and when DIM installs the product it deletes both of these files (if I've ticked the option to delete packages after installation).
If instead I go to my Product Library and download the manual installer (blue button) it downloads just the ZIP (i.e. 'IM00030698-01_UltraGenesis23.zip').
So the DSX is purely for DIM, whereas the ZIP just contains files to be unzipped to a content folder.
The ZIP contains at the top level a 'Content' folder and two more DSX files, 'Manifest.dxx' and 'Supplement.dsx'. When I manually installed products in the past I simply copied the contents of the 'Content' folder to whatever content library I wanted. I'm fairly certain that I asked about the 'Manifest.dxx' and 'Supplement.dsx' files on these forums (probably the old forums as I can't find the thread) and I believe that since I was not using CMS they were irrelevant for me, as they were used my DIM to add the product data to CMS.
The manifest seems to be an XML file telling DIM what to do with each file from the ZIP, and the supplement seems to be an XML file with just a couple of bits of data about the product. The separate DSX that the DIM downloads (e.g. 'IM00030698-01_UltraGenesis23.dsx' ) seems to be a slightly expanded version of the 'Supplement.dsx'.
Some content products (though not my example, but the Genesis Starter Essential) also contain another DSX file within the ZIP, under '/Runtime/Support/''.
There may be other DSX files but the four identified here (i.e. 'IM######_ProductName.dsx', ''Manifest.dsx', 'Supplement.dsx', and the DSX under '/Runtime/Support/'') seem to be the ones of most importance.
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Now that the CMS seems reasonably stable I'm reinstalling all of my Genesis content via DIM, and of course I'm now seeing stuff in the Smart Content pane for the first time.
So my query is this: what exactly is the relationship between the four DSX files, DIM, CMS, metadata and smart content ?
The obvious one to me (which may or may not be correct) is that DIM uses all four DSX files to set up the metadata for the product in the CMS database, and the Smart Content panes uses (a subset of) this metadata.