Packaged usually means a Freeware item (most likely from the DLS but there are exceptions) that has been included in a DLC "package" you have downloaded. Placing freeware assets in a DLC package makes them faster to download and the user does not then have to download them separately from the DLS (or another source). There are some assets that are labelled
Package, Payware that may not be possible to modify.
Packaged assets
usually can be modified like DLS assets BUT there is a issue. Like
Built-in and
Base assets, packaged assets have textures that are more highly compressed and stored in the .texture format, not in the .jpg, .png, .tiff, .tga formats used by DLS assets - this trick saves space and download time. So you will not be able to use graphic software to edit the textures unless you can convert the .texture file to a .png, .tga, .jpg, etc. There is a utility program available on the web that will do the conversion.
Look at
Shane Turner Tutorials - the PEVSoft page. The utility is called Images2TGA.
Of course, if you are going to modify anyone else's work and upload it to the DLS or anywhere else then you must get their permission to do so.