20988.rar File

Compressed archives with generic numeric names (like "20988.rar") are often used for private data transfers or, in some cases, to distribute malware. If you did not expect to receive this file, it is recommended to scan it with updated antivirus software before opening.

Specifically mentioned in "Detailed Statements of Expenditure on Public Works of Canada" spanning 1867 to 1892. 20988.rar

It is used for data compression, error recovery, and file spanning. Compressed archives with generic numeric names (like "20988

The portion of your query refers to a Roshal Archive file, a compressed archive format developed by Eugene Roshal. in some cases