GC1 file extension is for Golden Common Lisp 1.1 Lisp language source code file
Similar to GC1
$00 - DOS Pipe file
$1 - ZX Spectrum file in HOBETA format
$D$ - Data
OS/2 Planner
$DB - Temporary file
dBASE IV
$ED - Editor temporary file
MS C
$LN - TLink response file
Borland C++
$O1 - Pipe file
DOS
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