While the specific contents of "Reb1MF" are not indexed in public databases, this naming style is frequently used for large data transfers, such as:
Because this file is part of a set, it cannot be opened or extracted on its own. You will need all subsequent parts (e.g., .001 , .002 , .003 ) in the same folder to successfully access the contents. Technical Analysis 7-Zip Split Archive (Part 1). Reb1MF.7z.001
Right-click on the .001 file specifically. While the specific contents of "Reb1MF" are not
The file is a split archive file, specifically the first part of a multi-volume compressed archive created using 7-Zip. Reb1MF.7z.001
Large textures or "re-baked" (REB) game files.