To understand this file string, we must break down its technical nomenclature, the film itself, and the release group behind it. Anatomy of the File String

This indicates the source used to create this specific digital file. A "Blu-ray" tag means the encoder ripped the data from an official commercial Blu-ray Disc. This guarantees a high-quality baseline image, free from the watermarks, television logos, or compression artifacts found in "HDTV" or "DVD" rips. 3. "720p" (The Video Resolution)

This refers to the audio codec (Dolby Digital). AC3 is a standard for multi-channel surround sound, ensuring that the clashing swords and trebuchet fire of the 14th century sound immersive on a home theater system.

But then, the third wave of comments:

In an era of 4K streaming, why would someone look for a 720p x264 rip?

The BluRay release became the gold standard for fan encodes, including the one referenced in our keyword.