Transition apt sources from old sources.list format to deb822 format

[JedMeister]

For some time, apt has supported a newer alternate format to the older one line style used in apt sources.list repo files. This newer format is called deb822 (in a .sources file).

As I understand it, one of the main rationals is that the newer style is easier to parse, for both machines and humans. One of the cool features IMO is that the (ascii armored) key can be included in the file too.

To give an example of our current Bookworm repo (although usually doesn't include arch):

# cat /etc/apt/sources.list.d/turnkey.list
deb [arch=amd64, signed-by=/usr/share/keyrings/tkl-bookworm-main.gpg] http://archive.turnkeylinux.org/debian bookworm main

# cat /etc/apt/sources.list.d/turnkey.sources
Enabled: yes
Types: deb
URIs: http://archive.turnkeylinux.org/debian
Suites: bookworm
Components: main
Architectures: amd64
Signed-By: /usr/share/keyrings/tkl-bookworm-main.gpg

However, as I noted, the key can be included in the actual .sources file. E.g.:

# cat /etc/apt/sources.list.d/turnkey-alt.sources
Enabled: yes
Types: deb
URIs: http://archive.turnkeylinux.org/debian
Suites: bookworm
Components: main
Architectures: amd64
Signed-By:
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IMO we should implement this new style in v19.0.