: Frequently seen when splitting large system data or "SD card" backups into smaller chunks for easier downloading.
: Often used for SD card images for devices like the ArkOS or R36S . SD.7z.003
7 Easy Ways to Open 7z Files: WinZip, 7-Zip, & More - wikiHow : Frequently seen when splitting large system data
To "make text" or access the content from this file, you must first the full archive. You cannot open part .003 on its own. How to extract the contents SD.7z.003
: The software will automatically find the other parts and combine them into the original file or folder.
If you'd like, I can help you find a specific for your computer or explain how to re-split your own large files.