The cipher algorithm used by default, is dependent on your system/preferences and version of GPG. My Debian 9 system's default is AES256. To see the list of ciphers available to you, under Ciphers; run (via CLI):
gpg --version
Gitenc will use the default. You can override by appending your choice (using CAMELLIA256 in the example):
gpg --cipher-algo CAMELLIA256 # the cipher you want to use
to the line in the lockdown() function from the source, like so:
"$GPG_LOC" --batch -c --cipher-algo CAMELLIA256 --passphrase-file "$GITENC_CONF" "$1"