The "8sk" suffix often appears in community-modified versions of emulators, sometimes associated with specific "skins," "sketches," or developer handles. Since I cannot open the file directly, here is the general context of what a "Nester" zip file typically contains:
Supporting files required for the emulator to interface with your hardware. Nester8sk_Old.zip
A file like Nester.exe used to run NES games on a PC. readme
readme.txt or changes.txt files explaining the specific "Old" version's features or bug fixes. sometimes associated with specific "skins
.ini or .cfg files that store user settings, button mappings, and video preferences.
Are you trying to with this version of Nester, or
If you are looking for a specific text output from the zip, such as a or a license agreement , you will need to extract the archive on your device and open the .txt or .doc files located inside.