The -RBG tag is a tribute to a lost giant. For anyone active in the digital media space before 2023, downloading an RARBG release was a weekly ritual. Seeing that tag in a file name brings a wave of nostalgia for a time when discovering a new, perfectly-encoded movie was as simple as a quick search on a clean, reliable site.
This signifies the source of the video file. A is a rip created from a streaming source (like Amazon Prime Video or iTunes). The 1080p indicates the vertical resolution is 1080 pixels, making it a high-definition (Full HD) copy. Devil.In.The.Flesh.1998.1080p.WEBRip.x264-RBG