/usr/share/applications/gnome-disk-image-mounter.desktop is in gnome-disk-utility 3.18.3.1-1ubuntu1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 | [Desktop Entry]
Name=Disk Image Mounter
Comment=Mount Disk Images
Exec=gnome-disk-image-mounter %U
Icon=drive-removable-media
MimeType=application/x-cd-image;application/x-raw-disk-image;
Terminal=false
StartupNotify=false
Type=Application
NoDisplay=true
X-Ubuntu-Gettext-Domain=gnome-disk-utility
|