The Nextcloud desktop client keeps photos and documents always up to date, enabling you to work like you always did.
Any file you add, modify or delete in the synced folders on your desktop or laptop will show up, change or disappear on the server and all other connected devices.
Nextcloud features that put you in control
Technologies
C++ and Qt
What is C++?
C++ is a cross-platformed language that can be used to create sophisticated high-performance applications.
You can try some C++ here http://cpp.sh/
What is Qt?
Qt is used for developing graphical user interfaces (GUIs) and multi-platform applications that run on all major desktop platforms and most mobile or embedded platforms.
Repository
To checkout the code, run in your terminal:
$ git clone https://github.com/nextcloud/desktop.git
Remember that the desktop client is the means to connect to a Nextcloud server to sync files. To quickly get an account for testing the desktop client you can access https://try.nextcloud.com/ - click on I just want a short look around.
Nextcloud Files - Open source file sync and share platform
Development setup guide
The basic info you can find here: https://github.com/nextcloud/desktop/blob/master/README.md and here Home · nextcloud/desktop Wiki · GitHub.
Open to beginners
Yes 
Code of conduct
Good first issues
Issues · nextcloud/desktop · GitHub
Contact
You can find me at 
hello@camila.codes and on 
twitter.com/camilacodes.