Without the specific source or full set of files, it is impossible to know the exact contents, but it is typically a firmware binary file , a source code project folder , or project documentation for an ESP chip project.
I can help determine the exact nature of the file and how to use it. esp628.part1.rar
Download all .part files associated with this project (e.g., .part2.rar , .part3.rar ) into the same folder, then use a tool like WinRAR or 7-Zip to extract them. If you can share: Without the specific source or full set of