Ski Bundle - I should have waited

@mathmathou
Just look inside and see if there's a Content folder and a Manifest.dsx (there should be if it's actually an installer zip)
If so, simply rename the Zip. Being a Daz product, it will have a /Runtime Support/<product>.dsx file. The name of this file gives you all you need to know to accurately reconstruct the original name. the DSX nomenclature is:
[STORE]_[SKU]_[PRODUCT_NAME].dsx
The product name always has spaces and illegal special characters replaced by underscore "_".
If there's no metadata file (older products may not have one), you can also find the canonical product name in Supplement.dsx, in the <ProductName VALUE="..."/> tag. SKU can be had from external sources as well.

Now the installer nomenclature is:
[CATALOG]-[VOLUME]_[ProductName].zip
All three parts are required.
[CATALOG] must be at least ONE alphabetic character and no more than 7, followed by at least 8 numeric characters, up to the maximum length.
The total length of [CATALOG] is at least 9 chars and no more than 15 chars maximum. It must be followed by a dash "-"

[VOLUME] is always a two digit number from 01 to 99. It must be followed by an underscore "_"

[ProductName] is the canonical product name as it appears in the store and internally in the metadata. It is always in caps-case, with spaces and illegal characters stripped. It cannot contain any underscore "_"

Knowing this, naming a valid installer zip becomes trivial:
for example, you find DAZ_3D_85608_Mountain_Rescue_Helicopter.dsx
We know Daz's prefix is IM, and we have the SKU, so
[CATALOG] becomes IM00085608 (the SKU is zero padded to get the 8 digits minimum);
it's the only package of its SKU, so the single [VOLUME] is 01;
and [ProductName] is derived by simply stripping out the underscores and ensuring caps-case, to become MountainRescueHelicopter
Therefore the complete filename will be
IM00085608-01_MountainRescueHelicopter.zip

Know that this nomenclature is exact, and must follow this form for DIM to be able to recognize a Zip file as an install package. DIM only reads the filename to accept or reject a file, only then does it open the file to install the Content.

One more thing;
in the absence of a <support>.dsx file (metadata file), Daz will get the product token from [CATALOG]. Daz only recognizes IM (as the stores "DAZ_3D" and "LOCAL_USER") for stripping out the SKU. Any other prefix is allowable, but if it is not "IM", the prefix is hashed and prepended to the remaining numeric characters in order to make a fully numerical token for inclusion in the Content DB.
If the product is "mature", that is, it contains properly formatted metadata dsx file, then the actual SKU defined therein will be used. If a store is defined, that does not already exist in the DB, then LOCAL_USER will be default.
But none of this matters to simply getting DIM to eat a Zip snack 🙂