How to retrieve plain text from encrypted Bash Shell Script with SHC on Linux

Dears,

i have this case, i come to a project, where i found someone before me created a backup scripts that are in format backup.sh.x and backup.sh.x.c and there is also backup.sh.gpg, now i need to make a modification to this backup script to preclone before starting the backup.

i read that these scripts are compiled with shc with below two commands,

shc -vf backup.sh

gpg -C backup.sh

and no one knows who created that script but only they know the script exists "as is"

can someone advise me how i can make modifications to this script ? or at least view it  ?