$ sudo apt-get update
$ sudo apt-get install libkf5mailtransport-data 

libkf5mailtransport-data is installed in your system.

Make ensure the libkf5mailtransport-data package were installed using the commands given below,

$ sudo dpkg-query -l | grep libkf5mailtransport-data *

You will get with libkf5mailtransport-data package name, version, architecture and description in a table

libkf5mailtransport-data package basic information: