[Lazarus] ppa repository for Ubuntu derivatives

[Juha Manninen]

There has been talk earlier about putting up an update server for some
Linux distros, providing latest versions of FPC and Lazarus.

I updated the latest version of QupZilla browser into my Mint 17. I ran this :
 $ sudo add-apt-repository ppa:nowrep/qupzilla
according to the instructions and now I have the latest version 1.8.6.
The one in Mint repos was > 2 years old, which is typical with
non-mainstream SW.
Their download page is nice BTW:
  http://www.qupzilla.com/download

Question: what is this "ppa" repository? How to set it up? This may be
a stupid question but I don't know such things.
Ubuntu + derivatives would cover already many users.

Juha