The .8Bi extension represents a . For Nikon users, the Nikon NEF.8Bi or similarly named Camera Raw.8Bi files are what bridge the gap between your camera's raw sensor data and your editing suite.
If your Nikon NEF files won't open, follow these steps to update your workflow: Photoshop Elements 2021 Nikon NEF files - Adobe Community
If you’ve ever tried to open your latest Nikon shots in an older version of Photoshop and were met with an "unsupported file" error, you’ve likely encountered the file. This specific file is a critical plugin component for Adobe Camera Raw (ACR) that allows Adobe software to interpret Nikon’s proprietary Electronic Format (NEF) . What is the .8Bi Plugin?