What does Boxing Day have to do with boxing?
1560s, from Dutch tragelen, from Middle Dutch traghelen "to drag," from traghel "dragnet," probably from Latin tragula "dragnet." Related: Trawled; trawling.
To sift through large volumes of data (e.g. Usenet postings, FTP archives, or the Jargon File) looking for something of interest. [Jargon File]