Most users search for this string because their tablet is stuck on the "Android" loading logo (a bootloop) or they have forgotten the pattern lock and cannot access the recovery menu. Because these tablets were "generic," there is no official manufacturer website to visit for a download.
If you have located the .tgz or .rar file containing this specific build, the installation process for WM8850 devices is unique:
Often refers to the specific LCD panel or the firmware build version.
Refers to the Wi-Fi chip (likely the Realtek RTL8188 or similar).
Stands for "Mobile Internet Device" with a 7-inch screen.
This happens if the "8223" driver isn't initialized in the firmware script.