ADVENT.INF and ADVENT.Z5 are the Inform source code and Z-Machine executable of Colossal Cave Adventure for the Spectrum 48K, created as follows:

1. The .TAP image was downloaded from World of Spectrum: 
   http://www.worldofspectrum.org/infoseekid.cgi?id=0006099
   http://www.worldofspectrum.org/pub/sinclair/games/c/ColossalCaveAdventure.tap.zip
   http://www.worldofspectrum.org/pub/sinclair/games/c/ColossalCaveAdventure.tzx.zip

2. It was loaded into the Spectrum emulator, Spectaculator and saved as a .SNA snapshot.

3. The snapshot was converted to .INF and .Z5 using John Elliot's Unquill utility:
   http://www.ifarchive.org/indexes/if-archiveXprogrammingXquill.html
   http://www.ifarchive.org/if-archive/programming/quill/unquill.zip