While there are no academic "papers" about that specific pirate release string, there are several insightful reviews and analyses of the movie and the series itself that explain why this entry in the franchise is significant. 🎥 The Movie: Gintama 2 (2018)

Since you asked for a “helpful story,” here’s one based on what often happens in such cases:

BDrip: This signifies that the source material was a retail Blu-ray Disc. This usually guarantees the highest possible visual fidelity compared to "WebRips" or "Cam" versions.

2. The Source & Quality

• 2018: The year the movie was released.
• bdrip: This stands for Blu-ray Disc Rip. It means the file was created by copying the video data directly from a retail Blu-ray disc. This usually indicates high video quality (better than a CAM or WEB-DL).
• x264: This indicates the video codec used to encode the file. x264 is a very popular, high-performance library for encoding video streams into the H.264/MPEG-4 AVC format. It is standard for HD video files (usually 720p or 1080p).

This string is a file release title commonly found on torrent sites, file-sharing forums, or Usenet. It contains specific technical information about the file, the source, and the group that released it.

Part 2: The Crisis: Things take a serious turn when the Shinsengumi face an internal power struggle. A cursed "otaku" sword transforms the cool Vice-Commander Hijikata into a cowardly, anime-obsessed loner. Meanwhile, Kamotaro Ito (Haruma Miura) stages a coup that threatens the very foundation of the special police force. Why You Should Watch It

It looks like you’re referencing a specific file naming convention for a fansub or encode of Gintama (likely episode 220, in BDrip x264 format), with “regretetmovies” and “upd” possibly being tags from a particular release group or an auto-generated filename.

If you're interested in watching Gintama or similar anime, there are several legal platforms where you can stream or purchase episodes, such as Crunchyroll, Funimation, and HIDIVE, which often provide high-quality streams or downloads with official subtitles and support for the creators.