Как я получаю включенный repos?

Это зависит, на каком выходном формате Вы хотите.

apt-cache policy показывает, что текущие источники с приоритетом относились к каждому:

~ apt-cache policy
Package files:
 100 /var/lib/dpkg/status
     release a=now
 500 http://ppa.launchpad.net/webupd8team/java/ubuntu xenial/main i386 Packages
     release v=16.04,o=LP-PPA-webupd8team-java,a=xenial,n=xenial,l=Oracle Java (JDK) 8 / 9 Installer PPA,c=main,b=i386
     origin ppa.launchpad.net
 500 http://ppa.launchpad.net/webupd8team/java/ubuntu xenial/main amd64 Packages
     release v=16.04,o=LP-PPA-webupd8team-java,a=xenial,n=xenial,l=Oracle Java (JDK) 8 / 9 Installer PPA,c=main,b=amd64
     origin ppa.launchpad.net
 500 http://ppa.launchpad.net/ubuntu-wine/ppa/ubuntu xenial/main i386 Packages
     release v=16.04,o=LP-PPA-ubuntu-wine,a=xenial,n=xenial,l=Wine Team PPA,c=main,b=i386
     origin ppa.launchpad.net
 500 http://ppa.launchpad.net/ubuntu-wine/ppa/ubuntu xenial/main amd64 Packages
     release v=16.04,o=LP-PPA-ubuntu-wine,a=xenial,n=xenial,l=Wine Team PPA,c=main,b=amd64
     origin ppa.launchpad.net
 500 http://ppa.launchpad.net/jonathonf/vim/ubuntu xenial/main i386 Packages
     release v=16.04,o=LP-PPA-jonathonf-vim,a=xenial,n=xenial,l=Vim,c=main,b=i386
     origin ppa.launchpad.net
 500 http://ppa.launchpad.net/jonathonf/vim/ubuntu xenial/main amd64 Packages
     release v=16.04,o=LP-PPA-jonathonf-vim,a=xenial,n=xenial,l=Vim,c=main,b=amd64
....

Информация здесь может использоваться в другой способной конфигурации, как Кв. preferences или конфигурация для unattended-upgrades.

Можно также использовать API Python:

#! /usr/bin/env python3
import aptsources.sourceslist
sources = sourcesList.SourcesList()
for source in sources:
    if not (source.disabled or source.invalid):
        print(source.line.strip())

Который дает вывод как:

deb http://jp.archive.ubuntu.com/ubuntu/ xenial main restricted
deb-src http://jp.archive.ubuntu.com/ubuntu/ xenial main restricted
deb http://jp.archive.ubuntu.com/ubuntu/ xenial-updates main restricted
deb-src http://jp.archive.ubuntu.com/ubuntu/ xenial-updates main restricted
deb http://jp.archive.ubuntu.com/ubuntu/ xenial universe
deb-src http://jp.archive.ubuntu.com/ubuntu/ xenial universe
deb http://jp.archive.ubuntu.com/ubuntu/ xenial-updates universe
deb-src http://jp.archive.ubuntu.com/ubuntu/ xenial-updates universe
deb http://jp.archive.ubuntu.com/ubuntu/ xenial multiverse
deb-src http://jp.archive.ubuntu.com/ubuntu/ xenial multiverse
deb http://jp.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
deb-src http://jp.archive.ubuntu.com/ubuntu/ xenial-updates multiverse
deb http://jp.archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
deb-src http://jp.archive.ubuntu.com/ubuntu/ xenial-backports main restricted universe multiverse
deb http://security.ubuntu.com/ubuntu xenial-security main restricted
deb-src http://security.ubuntu.com/ubuntu xenial-security main restricted
deb http://security.ubuntu.com/ubuntu xenial-security universe
deb-src http://security.ubuntu.com/ubuntu xenial-security universe