> A a description of the problems that it solved.

Don't believe the hype.

>

> "Problems with the One-Line-Style Format begin when parsing
> entries via machine. Traditional, optionless entries are
> relatively simple to parse, as each different portion of the
> entry is separated with a space. With options, however, this is
> no longer the case. The presence of options causes there to be
> no, 1, or multiple segments of configuration between the type
> declaration and the URI. Additionally, APT sources support a
> variety of URI schemas, with the capability for extensions to add
> additional schemas on certain configurations. Thus, supporting
> modern, optioned One-Line-Style Format source entries requires
> use of either regular expressions or multi-level parsing in order
> to adequately parse the entry. Further compounding this support
> is the fact that One-Line-Style Format entries can have one or
> more components, preventing parsing of sources backwards from the
> end towards the front.

Read the above thoughtfully, regular expressions or multi-level parsing has been the cornerstone of *nix Os'es for decades, that already exists in abundance.

What they have ommitted to say is...

"It is pure coincidence that this resembles the schema used by SystemD and we have absolutely no intention of integrating package management and updates into SystemD with minimal effort on our part and use the configuration file parser we have already written".