Often refers to specific model numbers for television sets, satellite, or security devices. SW: Stands for "Software" or "Firmware."
Because this file is part 28 of a multi-part split ( .part28.rar ), it is and requires all other parts (part01 through at least part28, and possibly more) to be present in the same folder to successfully extract the files [1]. 🛠️ What is a .part#.rar File? LE90_SW_DD.part28.rar
Use anti-virus software to scan all downloaded parts before attempting to extract them, as multi-part archives can sometimes conceal malicious files [1]. Often refers to specific model numbers for television