This string is a standard (or NFO-style header) used in the warez and piracy scenes to identify a specific video file. It tells you the quality, source, and the group that released it.
Here is the breakdown of what makes this post "useful" information for a downloader: 1080p.web.h264-ethel
A standard, baseline acceptable WEB-DL. It is likely not the best quality available, but it is also not a scam or fake. You get exactly what the filename promises: 1080p, from a web source, using H.264 encoding, released by a lower-tier group. This string is a standard (or NFO-style header)
Helps trackers verify file integrity and prevent duplicate listings. The Role of WEB-DLs in Modern Archiving from a web source