I was a bit surprised to hear about it but I have so much to learn anyway that I couldn't let the fact I hadn't heard of it be too big a factor in my thinking.
I make extensive use of the tools used by Synaptic for basic research on packages in Debian. I use them on the cli because they are easier and more convenient to use there. You can open a number of queries in tabs in the cli so you can compare the depends and descriptions of different packages whereas you can only see one at a time in the gui.
These are all apt-cache tools like apt-cache policy (installed or not and what versions are available), apt-cache show (the description and depends and what repo it is in and so forth) and apt-cache search.
Using those it is also easy to open several tabs of a web search on a web browser and copy/paste package names or the home pages for different applications that are listed in any of those tools.
Pretty good way to get my aging brain confused and bewildered.
One reason I have so many installs is that I can dedicate different installs to be used for particular types of application installs. Appears that I am trending, once again, toward security related packages.