First of all let me correct you, .spk isn’t a format, it is a Extension that contains in specific softwares to let it open or let it view or convert. 2nd of all there is no Official information so far about .SPK files that what it does and why it exists. But there are specific programs that opens it and give you few solutions too.
Programs that open SPK files:
- Apple Archive Utility
- Smith Micro StuffIt Deluxe 16
- GNU Tar
- The Unarchiver
SPK files are saved in the .TAR format. Therefore, you can also open them with any TAR archive extractor.
Software that will open, convert or fix SPK files:
- Parallels Tools Center
- Universe Plugin Manager
- Media Player Classic
- Plugin Manager - Packager
In addition to the products listed above, I would suggest that you try a universal file viewer like Free File Viewer. It can open over 200 different types of files - and very likely yours too! Download Free File Viewer.
@s_b Google does help, Until unless you use correct keywords, So please google search and try to find your solution. Don’t say solution not exist anywhere, Actually you haven’t reached to it so far, so kindly research and find out where it remain hidden or visible. That’s all mate!