Software diagnostics or server-side archives may generate these names automatically during a backup or crash dump.
Compressed fragments of SEC filings (such as those from Overstock.com) sometimes contain encoded strings or headers that include the "JT/RAR" signature as part of their data transmission protocols. Jt.rar
However, files with this naming convention often appear in the following contexts: such as trojans or ransomware
If you received this file from an unknown source via email or a download link, do not open it . .rar files are frequently used to hide malware, such as trojans or ransomware, because the compression can bypass basic email scanners. Jt.rar