The answer lies in the information provided when you add the ppa:
sudo add-apt-repository ppa:embrosyn/xapps
This PPA contains builds of X-Apps for Ubuntu. X-Apps are a bunch of GTK3 DE-agnostic applications that are not so tightly tied to a particular distribution or DE as their ancestors (forkees) might be, developed by the Linux Mint crew:
* pix (image management application based on gThumb)
* xed (text editor based on Pluma),
* xplayer (media player based on Totem),
* xviewer (image viewer based on Eye of GNOME), and
* xreader (document reader based on Atril)
When nothing goes horribly wrong, this PPA should have the same packaging tempo and distribution series set as my Cinnamon PPA - the latest long-term support (LTS) and short-term (STS) releases, which currently means:
* Ubuntu 18.04, Bionic Beaver (bionic) [LTS],
* Ubuntu 19.04, Disco Dingo (disco) [STS].