The song itself has a legendary backstory often detailed in "feature-style" retrospectives:

: The isolated intro rap, which was added later to provide a "swaggering contrast" to the emotional core of the song.

If you have come across a .rar file of this nature, it likely contains the high-fidelity individual components of the song:

While there is no official "umbrella.rar" software or major media project, the name appears most frequently in digital archiving circles as a for Rihanna’s 2007 smash hit "Umbrella." These files are often sought after by music producers and remixers to deconstruct the track's iconic layers. The Anatomy of the "Umbrella" Multitracks

: Dry vocal tracks (without reverb) and wet tracks for Rihanna's lead vocals, backing harmonies, and the famous "ella, ella" hook.