Pianoextra02.rar -

A batch of PDF scores, possibly part of a series (given the "02" suffix).

Based on the naming convention typically used in niche music production and digital sheet music communities, it most likely contains one of the following: pianoextra02.rar

A collection of MIDI sequences for piano performances, often used for synthesizers or learning software like Synthesia. A batch of PDF scores, possibly part of

If you downloaded this from a forum or a peer-to-peer site, check the comments or the "readme" file inside for the creator's name. Run the file through a service like VirusTotal

Run the file through a service like VirusTotal before extracting.

High-quality audio recordings (WAV or AIFF) of a specific piano meant to be loaded into a sampler like Kontakt.

Could you tell me or what you expected it to be ? Knowing the context or the file size would help me provide a much more detailed review of its contents.