update-desktop-database: not found

I downloaded Debian package and tried to install it with the following command on Ubuntu 24.04 on WSL2:

sudo dpkg -i /mnt/c/Users/dmitr/Downloads/v2rayN-linux-64.deb

But got the following error:

Selecting previously unselected package v2rayn.
(Reading database ... 55910 files and directories currently installed.)
Preparing to unpack .../Downloads/v2rayN-linux-64.deb ...
Unpacking v2rayn (7.14.3) ...
Setting up v2rayn (7.14.3) ...
/var/lib/dpkg/info/v2rayn.postinst: 14: update-desktop-database: not found
dpkg: error processing package v2rayn (--install):
installed v2rayn package post-installation script subprocess returned error exit status 127
Errors were encountered while processing:
v2rayn

What does it mean?

What it means is that there is an unfulfilled dependency of the v2rayn package. As part of its installation process, it's looking for a script or executable update-desktop-database that was in the dependency, and can't find it. This can happen if you try to install downloaded .deb packages; by downloading the raw package, you either lose or ignore the dependencies for that package.