The Screen Rant YouTube video below is more of a fan theory but I think it is a pretty good analysis of the plumbus. The video itself admits that there are a few holes in their theory's conclusion of what exactly a plumbus does but as a best guess it seems sound.
As a fictional technology the plumbus is rather special. In most fiction the technology featured has at least a little exposition. By apparent luck in most common fiction the characters just happen to be talking about the technology in a way that gives some clue to help the audience understand it. Rick and Morty goes the "show don't tell" route and just presents the fictional plumbus as is. Similar to how in in a Hollywood movie someone doesn't enter a room, flick the light switch and talk about the filament inside an incandescent bulb.
It's fascinating to think about technology being available in almost every possible reality in the multiverse that exists similar to "ours" but somehow "we've" missed out on it. In a way though there are plumbuses in our universe but different. A few months ago 
The Rick Sanchez (Justin Roiland) the Rick and Morty series presumably follows seems to not have known how a plumbus was made until he saw an episode about the process on "How They Do It". It seems like a genius inventor would immediately try to find out or reverse engineer the item once he first saw one. Rick isn't exactly a "reliable narrator" and might have been feigning ignorance since at the time Rick was considered a wanted terrorist by the Galactic Federation and he was visiting an alien hospital.
Apparently at least one version of Rick in the central finite curve not only found out about the process of plumbus production but exploited it for personal gain. In the "Pocket Mortys" video game enslaved Mortys on Plumbubo Prime 51b manufacture plumbuses.
