The ".LEG.B..." suffix typically stands for Legenda (Subtitles) and Brasil/BR (Brazilian Portuguese) in file-naming conventions.
In the context of a file request or download confirmation, a more professional and user-friendly way to present that message would be: " Title: CSI: Vegas Episode: Season 2, Episode 9 Format: MP4 Subtitles: Portuguese (LEG) / Brazilian (B...)" Clearer Text Options
"Request Processed: CSI.Vegas.S02E09.MP4.LEG.BR "