libkdeclarative5 software package provides declarative library for plasma, you can install in your Debian 8 (Jessie) by running the commands given below on the terminal,
$ sudo apt-get update $ sudo apt-get install libkdeclarative5
libkdeclarative5 is installed in your system.
Make ensure the libkdeclarative5 package were installed using the commands given below,
$ sudo dpkg-query -l | grep libkdeclarative5 *
You will get with libkdeclarative5 package name, version, architecture and description in a table
| Distro | Debian 8 jessie |
| Section | Libraries |
| Package | libkdeclarative5 |
| Version | 4:4.14.2-5+deb8u1 |
| Description | declarative library for plasma |
| Sub Section | libs |