/usr/sbin/mwenext is in mediawiki-extensions-base 3.6.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32  | #!/bin/sh
# Enable a mediawiki extension
extension=$1
name=`echo $0 | perl -e 'while (<>) { s/(?:.*\/)?(.*)$/print "$1\n";/e }'`
if [ $name = "mwdisext" ]; then 
  if [ ! -f "/etc/mediawiki-extensions/extensions-enabled/$extension" ]; then
    echo "Extension not enabled !"
    exit 1
  fi
  rm "/etc/mediawiki-extensions/extensions-enabled/$extension"
  echo "Extension $extension disabled !"
fi
if [ $name = "mwenext" ]; then
  if [ ! -f "/etc/mediawiki-extensions/extensions-available/$extension" ]; then
    echo "Extension does not exist !"
    exit 1
  fi
  if [ -f "/etc/mediawiki-extensions/extensions-enabled/$extension" ]; then
    echo "There is already a file at /etc/mediawiki-extensions/extensions-enabled/$extension !"
    exit 1
  fi
  ln -s "/etc/mediawiki-extensions/extensions-available/$extension" "/etc/mediawiki-extensions/extensions-enabled"
  echo "Extension $extension enabled !"
fi
exit 0
 |