Focal daily ISO forces proposed

[corrado venturini]

Installed Ubuntu 20.04 from daily ISO Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200622)
doing apt update i see proposed but i never activate proposed and i'm unable to deactivate proposed by 'software ans updates'

corrado@corrado-n7-focal:~$ sudo apt update
[sudo] password for corrado:
Get:1 http://archive.ubuntu.com/ubuntu focal-proposed InRelease [265 kB]
Hit:2 http://it.archive.ubuntu.com/ubuntu focal InRelease
Get:3 http://it.archive.ubuntu.com/ubuntu focal-updates InRelease [107 kB]
Get:4 http://security.ubuntu.com/ubuntu focal-security InRelease [107 kB]
Get:5 http://archive.ubuntu.com/ubuntu focal-proposed/main amd64 DEP-11 Metadata [42,6 kB]
Get:6 http://it.archive.ubuntu.com/ubuntu focal-backports InRelease [98,3 kB]
......

I find proposed in sources.list.d

corrado@corrado-n7-focal:~$ cat /etc/apt/sources.list.d/proposed.list
deb http://archive.ubuntu.com/ubuntu/ focal-proposed main restricted
corrado@corrado-n7-focal:~$

I have the same problem with another install from Ubuntu 20.04 LTS "Focal Fossa" - Release amd64 (20200618)

I would like to open a bug but I don't know which package to report
thanks

[corrado venturini (corradoventu)]

see https://answers.launchpad.net/ubuntu/+question/691488

[Paul White (paulw2u)]

See bug 1879373 for explanation of why -proposed is enabled.