Manage your system's Personal Package Archives (PPA) repository sources.
Repo is available from via AppCenter for elementary OS.
You can install Repo by compiling it from source.
Ensure you have these dependencies installed beforehand:
meson
vala
glib-2.0
gobject-2.0
gtk+-3.0
>= 3.18gee-0.8
granite
>= 0.5.0software-properties-common
Run make build
in the project's root folder.
Run make install