In Wikipedia, under Linux Mint, it says :
Linux Mint divides its software repositories into four main channels that reflect differences in their nature and in their origin.
Provides only software that is developed by Linux Mint.
Provides software which is present in Ubuntu but patched or modified by Linux Mint. As a result, the software provided by this channel behaves differently in each distribution. Notable examples are Grub, Plymouth, Ubiquity, Xchat, USB Creator and Yelp (the help system).
Provides software that is not available in Ubuntu or for which no recent versions are available in Ubuntu. Notable examples are Opera, Picasa, Skype, Songbird, the 64-bit Adobe Flash plugin and Frostwire.
Not enabled by default. Provides test packages before they are promoted to other (stable) channels. As such it represents the unstable branch of Linux Mint.
Is this true ? If so, which repository(ies) shown in Synaptic Package Manager corresponds to each of the above ?
If it's not true, where can I find a description of the function and the content of the repositories I see in Synaptic Package Manager ?
If I run inxi -r I see
http://packages.linuxmint.com debian main upstream import
and no mention of 'romeo' which seems to imply the above classifications are no longer relevant.