2 items:
 (BIN) grackle.zip
       [11-Mar-2011]
       Grackle 0.4 beta, by David Lodge. A dumper and player for
       adventures written using the Graphic Adventure Creator. It
       supports GAC games from the Spectrum, Amstrad CPC and BBC
       B Micro. Archive includes C source and an MS-DOS executable.
       
 (BIN) ungac.zip
       [15-Sep-2018]
       UnGAC version 0.1, by John Elliott. UnGAC reads a snapshot of
       a Spectrum adventure game created with Incentive's Graphic
       Adventure Creator and produces text listings of the game data.
       Archive includes C source, executables for Win32, CP/M, and DOS,
       and documentation.
       
       
       The IF Archive is a public service of the
       Interactive Fiction Technology Foundation.
 (HTM) http://iftechfoundation.org/
       
       This mirror is a public service of 661.org.
 (HTM) http://661.org/