Without more context, it is difficult to provide a "review" of the actual data inside. However, these specific numbered files often appear in the following communities:
Numbered lists used in retro gaming collections (like No-Intro or TOSEC sets). 1266.7z.001
Right-click the .001 file and select "Extract." The software will automatically pull data from the other parts to reconstruct the original file. Identifying the specific content Without more context, it is difficult to provide
Use a tool like 7-Zip or WinRAR.