5800 Rom Rpkg Exclusive — Nokia

Crucially, like a ZIP file. They are data payloads for flashers. Trying to extract them with WinRAR or 7-Zip will result in gibberish.

: They are frequently used to set up Symbian emulators on modern hardware or to provide a "base" for creating custom firmware (CFW). nokia 5800 rom rpkg

In the context of Symbian modding, an file is a container used for distributing ROMs and firmware updates. Crucially, like a ZIP file