Thanks.
My sources.list says:
#
# deb cdrom:[Debian GNU/Linux 8.6.0 _Jessie_ - Official Multi-architecture
amd64/i386 NETINST #1 20160917-18:46]/ jessie main
#deb cdrom:[Debian GNU/Linux 8.6.0 _Jessie_ - Official Multi-architecture
amd64/i386 NETINST #1 20160917-18:46]/ jessie main
deb http://ftp.dk.debian.org/debian/ jessie main
deb-src http://ftp.dk.debian.org/debian/ jessie main
deb http://security.debian.org/ jessie/updates main
deb-src http://security.debian.org/ jessie/updates main
# jessie-updates, previously known as 'volatile'
deb http://ftp.dk.debian.org/debian/ jessie-updates main
deb-src http://ftp.dk.debian.org/debian/ jessie-updates main
It's one file - I don't know why it's divided here.
I have a sources.list.d folder but it's empty.